I put "MULTI" when I did my first Form1 on a BCM lower. Didn't know better. I cough it, called the ATF and was able to change it, got approved without being kicked back.
Agreed. Grant has the stripped lowers for $199 but when the compete lowers are in stick, he still sells them for under $400.
What's smart is that the stripped lowers use a different serial number prefix so they can't be passed as complete factory lowers on the secondary market.