Well last I checked you don't need to send forms into the ATF to buy a coke. Also can't some baffles in basic suppressors be made from washers available in a hardware store? If so shouldn't you need a form for these?
No. You don't need a form 1 to buy a coke but if you put a bottle on the end of your gun you have made that bottle into a NFA item. Do that and you best be ready to accept legal responsibility for what you have done. Same for washers in a pipe attached to the muzzle of your gun.