I recently read a little about the Roman fabricae and how they may have been used as a major source of weapons in post-Republic Rome (even earlier?). Is there any evidence indicating that Rome sold weapons produced in this manner to other states? I am not referring to traders selling small amount of weapons individually but rather "wholesale" exporting, much like the USA does today with its fighter jets and the like.
Well Roman weapons were quite specific to their way to wage war. The complexe formations and the way they used them were not necessarily unique but were definitly not for everyone.
Gladii for example were short, broad and pointy swords. Outside of a roman formation it was not really good as a weapon as it had low reach and only were efficient as a stabbing weapon used from behind a good old roman shield.
The pila were nothing special, just short spears that you would throw at the enemy. Everyone knew how to make a spear as it is basically the simplest weapon ever.
So basically roman weapons were either too specific to Roman warfare or were so common no one would be interested in buying them. In either case there was not much of a market.
Emulating the Roman formations and cohesion necessitated a professional army of well trained men and this was really expensive and took time to raise. It meant that only big centralized states would maybe have a use for those and big centralized states either had their own way to wage war or would be enemies or competitors to the Romans.