The 4473 is stored at the gun shop. If they went out of business then that paperwork was turned over to the ATF. If they were stripped lowers they should have been marked receiver not long gun or handgun. I am not a lawyer but I have worked for over 15 years between 2 gunshops and have filled out thousands of 4473’s. Hope this helps.
If the paperwork listed them as stripped lowers you can do what you want with them. If they listed them as rifle or pistol is where you would run in to a problem. Do you remember what the paper work said?
That’s the way it should be…however, in the past, I have had my Stripped lowers “designated” as “rifles” by the place that shipped them to my lgs, who also put “rifle” on the paperwork. At the time, I didn’t care, now I do.
(OP) So, it is arbitrary as to how they may have originally designated your lowers. As for finding out…good luck. ATF will be your resource; no clue as to how helpful they will be.
From what I’ve seen the caliber on the lowers marked as 5.56 or what ever caliber of the upper it came with. If you purchased a lower by itself it should be marked “multi caliber”.
If it were me, I’d just sell the Stripped lowers and buy a couple more that I KNOW are listed as other. But then I don’t relish the idea of a 20 year prison sentence and being stripped of what rights I have left if things were to go sideways…
In reality the AR lowers do not fit the codified description of a receiver in Title 27 ATF codes. There was a Federal case in (I think) Washington state that was dismissed against some retailer that sold a lower with out recording the 4477 form.
If it is not explicitly marked “pistol” or “rifle” it is an “other” and you should treat it as such.
“Let me see your AR so I can dig into mountains of paperwork from a defunct FFL and determine if it’s built the way the 4473 said it was going to be”, said no ATF agent ever!
Trust me, if the ATF is asking you that type of nonsensical minutia you got much, much bigger problems to deal with than a potentially falsified 4473.