SBT's story is that they submitted all the braces for approval, and they didn't receive any approval for two years, so they just assumed that the braces were o.k.
Assuming that is true, then SBT is run by dumb asses or kindergarteners - if you know you need gov't approval, you don't "assume" you have it because the gov't doesn't respond.
Remind me what happens after three business days of no response from a NICS check...