Mdl 1816 Harpers Ferry Markings

Hello All, I have a few Mdl 1816 Harpers Ferry Muskets and some other parts/pieces. I read/study as much as I can about the 1816 Model US musket and the Harpers Ferry made muskets. 1822 to 1844 dated muskets I have seen, all have a single digit number from "1" thru "8" stamped on every part but the lock and stock. I have never found that anyone has every attempted to explain these stampings.

Were these used so that one man could build several muskets w/out getting parts mixed up?

Were these used to I.D. the worker that built that musket?

Were these used in the conversion to perc. process to keep parts with the correct stocks?

Your thoughts............