Mercantilism was definitely a part of the early economy of the North Atlantic colonies. Manufacture, as u/bolUwUdo points out, just means something made, finished goods as opposed to raw materials, and the early colonies had little chance of doing much of it. Virginia set a commission to look into encouraging crafts in the colony, in the early 18th c., and it reported that any craftsman hoping to set up shop there had dismal prospects: very few population centers that would bring enough trade to any artisan, little development of roads and transport, very meager supply of expert labor and sources of supply. While they were talking about a big sparsely-populated rural landscape of plantations, the same sort of problem existed in most of the colonies.

As the colonies became better established, however, craftspeople did become established as well- the shortage of skilled labor made the colonies attractive to craftspeople wanting to emigrate. So, despite the intentions of the British government, the colonists soon began to make more of their own stuff. But with limits: a gunsmith in Lancaster Co. Pennsylvania would have ample supplies of wood, for stocking, and of far better quality than he could get in England. He could get wrought iron from colonial iron producers for forging his own barrels, and he could likely also scrounge enough scrap brass for casting. However, though he could make his own locks, he mostly found it more cost-effective to buy imported ones from England, where large special shops could make them more cheaply. There was no mass-production in the industrial sense, yet, but by dividing up tasks skilled workers could develop more efficiency than one generalist could muster, and the English labor costs were lower. A lot of gunlocks could be fit into a cask for shipping, as well. The Lancaster gunsmith could not compete with a lockmaker like Ketland. So, most Kentucky rifles of the period had imported locks. And, when the Revolutionary War broke out and the Americans attempted to make at least some of their own muskets, a major obstacle was that imported locks were no longer to be ordered from England.

Those specialist shops could often do very high quality work, as well. Washington would order an especially fine fowler from an English gunsmith, and ask his friend Thomas Jefferson to pick up a good pocket watch for him while Jefferson was ambassador in France. A specialist gunsmith shop, with a dedicated engraver and stock carver, could produce something fancier than a Pennsylvania shop with one or two workers. And the great number of steps required of many specialists to make a good pocket watch- and the tools and supplies for doing so- were difficult to achieve in the colonies.

But some items were not nearly as cost-effective to import, and relatively easy to make. Hatters were flouting the ban on manufacturing hats in Boston fairly early. Not as many hats would fit into a cask as gunlocks, would not survive as well, and the beaver pelts to make them were already being produced in the New World.

Bridenbaugh, Carl . Colonial Craftsmen (2001). Dovers, Paperback(2011).

You are right that one of mercantilism’s big stances was importing raw materials and exporting finished goods (they equated this with having that whole positive balance of trade, large monetary reserves thing). I am not too sure about metalworking, but the textile industry is talked about often by economic historians as there were obvious changes to the way they made things post-Industrial Revolution. For what counts as a manufactured good, it could be anything really made. If you check Johnson’s dictionary from the mid-1700s, “manufacture” could mean (1) “the practice of making any piece of workmanship” or (2) “anything made by art”. This is why mercantilists and their opponents tend to put the artisanal goods under that definition.

As for how things were produced, in Britain, there were different production methods. One was the putting-out system where clothiers would provide raw materials (things like animal fleece and plant fibers) and capital so that spinners, weavers, etc. could make the goods for piece rate wages. There was also the Kaufsystem, where villagers bought their own materials and then sold finished goods to merchants who would sell them to customers (“The Decline of Textile Prices in England and British America Prior to Industrialization” by Shammas 1994). The presence of a guild also had an impact on the system used as they were pretty influential in who could practice the arts, production, and trade. Whoever made textiles had access to things like looms or spinning wheels depending on what they wanted to do, and then could get money for those goods.

There is an interesting paper called “Textile Production and Gender Roles in China, 1000-1700“ by Francesca Bray (1995), on the textile industry in pre industrial china that mentions 4 different types of textile producing establishments. Bray lists (1) peasant households, (2) large elite households where a family head or mistress organized production of other household members, (3) state manufacturers using workers, and (4) urban workshops of different kinds. (3) and (4) had more complex production methods like drawlooms and would usually buy raw goods, whereas (1) and (2) would produce their own raw goods (silk and plant fibers) and use cheap/simple looms. Spain was also known to have royal textile manufactories with foreign artisans, though this was post 1700s (“Royal Textile Factories in Spain, 1700-1800” by Clayburn La Force 1964).