Whoa. People are crossing the streams here.
ATF approvals of a Form 1, build your own suppressors or a firearm/short barrel rifle, is about a month. They do need to be properly engraved per ATF regs. I had my local gun shop engrave professionally for $120 with an industrial laser this month.
Purchasing a pre-manufactured suppressor has a longer ATF approval time. They are pre engraved.
Please correct me if I misstated, but Think these issues need clarity. ATF's EForms Has terrible technology, but still works okay and is a great opportunity to complete easily.