Halo spot faced the holes on his M1919 right side plates (RSP is the receiver according to ATF) His RSP was the same as what has been sold as an 80% RSP by several manufacturers for years. By adding the spot faced holes (just location marked, not drilled) The ATF decided it was too complete and classified it as a 100% receiver, even though it was still a long way from actually being one.
They grabbed Halo's receipts and started knocking on doors. They confiscated 3 complete 1919s for "evaluation". Last I heard, it was in limbo. No more have been confiscated, but AFAIK, the others had not been returned. This had the ATF's desired effect anyway, as Halo stopped making plates. All this is well documented at the M1919 forum
I don't know about you, but until I see an approval letter by the ATF on the "blanks" I would not go near them. I don't want any surprises at my front door, down the road.