sorry for the delay
The $200 tax stamp is only good for one suppressor , they are issued to a specific serial number.. same goes for a short barreled rifle or full auto weapon.
With a form 1 suppressor you can't even (not supposed) rebuild your can , so say you get your paperwork and make a suppressor but your desgine would benifit from an extra inch of length and two baffles , well you need to get another $200 stamp and build another can , your not supposed to cut the origional one up in to little pieces that in no way resemble a suppressor part and make another one.