For the most part the AKM is the AK-47.

The original variant of the AK-47 was designed in 1947 but it didn't enter major production until 1950 while the AKM was produced starting in 1959. Now it's also important to remember that this was still just after world war 2 so not only was the Soviet Union eager to return to more peaceful concerns but their armories were filled to bursting with an ungodly amount of weapons from the war; so the Soviets even during those 9 years of making the first edition AK were not cranking them out by the truckload preparing for world war 3 like they would be later on in the cold war. In fact they weren't even common issue until 1956 so really. Many of the major improvements to the AKM actually concern making it easier to assemble, most importantly perhaps was the Soviets refining the process to stamp out the receivers.

Since world war 2 all gun receivers (the 'frame' of the gun that all other parts are attached to) had to be milled to be produced, meaning they take a giant block of steel the size of the receiver and then have to carve it out to the desired shape using large drills. A major step forward in this process was to simple take a piece of sheet metal, cut out all the notches and holes for bolts, and then to bend the whole thing into a U shape. The Soviets had wanted this originally for the AK but the technology wouldn't be there yet for a few more years.

The AKM on the other hand would begin to enter service just before the sixties as the cold war was heating up, the Berlin wall was being built, the metaphorical iron curtain was assembled, and countries like Vietnam were starting to chafe under the yoke of imperialist powers. The Soviets produced them in massive quantities both to export to revolutionary movements around the world and to ready itself for a potential clash with the Western powers of NATO. The AKM would serve until 1974 when the Soviets noticed the advantages of the 5.56 caliber cartridge over the 7.62x39 cartridge the Soviets were using at which point the AK-74 replaced the AKM in Soviet stocks; however many nations (including China, itself a massive guns manufacturer) would continue to produce the AKM style rifles. Soviets weren't so big on pesky capitalist notions of patents and as such the machinery and technical knowledge of how to make the rifles were given away like candy to communist nations by the Soviets.

The original AK-47 is by all accounts an oddity, made in relatively low numbers (albeit compared to the second most produced firearm in human history) for a short length of time before it's more famous brother entered the scene. If you want to identify an original style AK-47 look to the stock, the AKM inserts it's stock directly into the receiver while the AK-47 actually had a little metal external socket on the outside of the receiver.