You might be able to serialize the 80% lower, of course that's more leg work. For the price of a complete lower with pistol buffer tube in place isn't that bad. I think I have 125 into my Anderson lower.
Mine is an AM-15 Multi-Cal lower.
If you go that route, check off the PISTOL box on the 4473....UNLESS you have to register pistols in VA. EDIT: Make sure you retain a copy for your records, that way you can prove your intent.
