The "maker" of the NFA item, and the location of the maker (City, State) must be engraved on the NFA item. That means if you (your trust) turn a lower into an SBR lower, the name of the trust and its location must be engraved on the lower. If you make a silencer, same thing. If you buy either one as transfers from the maker to the trust as an owner, no engraving is necessary (since the maker will have already engraved it's name and location on the item).
The concept is simple: "make" an NFA item (Form 1), engraving is necessary; buy a premade NFA item via transfer (Form 4), no engraving is necessary.
P.S. - my trust name is "[my initials] Firearms Trust," but it could be almost anything.