Considering the same thing, and wasn't sure about the engraving either. Hopefully someone will offer some insight.I am waiting on the e-file form 1 that I submitted at the beginning of the month. I have a Sig P516 with a 10.5" barrel, and I want to put a standard Magpul stock on it. Do I need to have it engraved with my trust and location since it was originally designated as a pistol? If so, I will go to Southwest Engravers before making any changes to convert it to an SBR.