Question regarding anodizing

[Palmaris]

Hello guys. I tryed to use search, but got mixed result. So here is question, if I want to anodize AR lower and anodizing shop has no FFL, I need to be in premises of this shop entire time while they do my order? If I am there, is it legal to do this way? Do I have to be in production area, or I can wait in their main office?
Thanks a lot in advance.

[Gunsmith Dan]

You have to be physically present if they have no FFL while they handle your receiver (lower) and keep it in sight (you don't need to stand next to them) ..... any other parts (upper, controls, forearm etc.) are not considered the firearm so they can work on those without you being present at all.