Could we VolReg using CFARS just bare receivers?

[SiggleWiggle]

Question:

1. If one milled out an 80% AR lower to a fully functional receiver and engraved all info (name, city and state, model, caliber, serial), is it possible to just register only the RECEIVER through CFARS?

2. So no parts need to be installed onto the receiver in order to register it, it can just be the registered as receiver only?

THANKS