The British never imported any muskets for the colonists. The colonists imported parts from France, Germany and other countries, and raided British arms rooms. Some Revolutionary firearms can have anywhere from 2 to 5 different serial numbers on fabricated parts from different countries, while others completely fabricated by colonial gunsmiths will have no serial number anywhere.
1777 Sept. “24th Weather delightful. 4 or 5 shot exchanged begtween our [british] forging parties
and the rebels about 9 this morning. Early this morning our pickets in the fear fired at some straggling rebels.
This township of Norrington is very rebellious.
All the manufactures about this country
seem to consist of Powder, Ball, Shot, firearms and swords.
The army halted this day.” “Montresor`s Journal”, Scull, pp421 -474 ff
Interesting...kinda like 3D printing a lower receiver...very informative post! Thanks