First - Get a trust, absolutely, even though the rules recently changed, get a trust.

Second - I am not sure the engraving is a requirement. My attorney (I used an attorney for the trust) did not think the engraving was a requirement. I looked at the NFA requirements and am not sure either.

Perhaps someone with some real knowledge will chime in.

I will add, the engraving requirements I am referencing are words to the effect:
"JONES FAMILY TRUST"
"ANYTOWN, USA"

I used a commercially made AR lower, already having the "manufacturer's" markings on it. I simply replaced the upper with a SBR upper. My attorney said the "trust" engravings were not required because all the NFA requirements are already met. And I do not intend to sell it.

However, if you manufactured the lower from an 80% lower, the answer is probably different. You actually become the "manufacturer" of the firearm. The NFA engraving requirements are here, they start about page 43:

https://www.google.com/url?sa=t&rct=...87pS7Q&cad=rja

Also more information here, about 4 paragraphs in:

Do You Need to Engrave Your Form 1'ed SBR? - The Truth About Guns