Danger.
Whatever the ATF regards as 'suppressor components' is a bad thing without an approved Form 1 if you're making your own suppressor. *With* an approved Form 1, they'll also call that constructive possession if you have more *useable* components than necessary to construct your one-off homebuilt can. You'd better be de-milling/destroying excess materials as you wind your way through your little project.
ATF Tech Branch recently produced an opinion letter which claimed that just having multiple 'quick detach' mounts for suppressors per Form 1 was a violation. This is the subject of very intense debate recently because it conflicts with countless other ATF Tech Branch opinion letters and I'd rather not discuss this further.
Even if ATF sent another opinion letter out retracting their previous opinion, that wouldn't satisfy me.
Are you referring to flash or sound suppressors?