J
Not 100% true.
If it were in fact restricted length barrel (which could be done before verification) it could be verified as such and issued a restricted cert. no different than grandpas hi-power or new service found in the sock drawer. People register found restricteds all the time. The short barrel (or barreled upper) would however be a prohibited device by itself, but could be chopped or removed and destroyed, or sent to a firearms business for replacement.
Not all Lugers were prohibited either... Only the ones with the shorter 4" barrels.
Most swiss Lugers I believe are restricted.
I see what you are saying but then you run into a situation where two frames are using the same slide/barrel to make it restricted. In a practical sense the scenario I have presented is what would transpire. Someone without 12(6) can not possess a prohibited handgun even during a reverification procedure unless they are an executor to an estate. All other instances it must be in the possession of a business.
I'm not saying that you are wrong, but...the CFC would rather see it in the system than out.
I brought one in from the cold, it was pretty easy. Formerly registered mind you, but totally off the grid when I called.
One phone call and it was done.
Again, up to your CFO's discretion on how they interpret the regulations.