Yep, I do the same thing for the same reason, and I remove the ridge of metal on the outside of the knurling on the face of the receiver so the recoil lug fits flush.

I also blend the sharp corners of the lug abutments that'll smack a 223 case upon ejection and leave a dent.

You've probably got some good tips on clean up, too. Care to share your 12FV rework tips for the rest of us?