So I recently stopped by and bought a lower from a manufacturer with the intentions of making it an SBR after my approval comes in. Looking at the already finished SBRs they had for sale, the upper I'm looking to purchase has an 11.5" barrel and a Magpul MOE SL adjustable buttstock. I'll be registering the SBR under my trust. This leaves 2 questions:

1.) With the stock collapsed, which is how I will shoot it, the overall length is 27.5". Fully extended, as is the ATF wording, is 30.5". The paperwork he pre-filled out for me is for 27.5", which seems wrong but this shop sells a lot more of these things than I've ever bough.

2.) Once my approval comes back and I purchase the specified upper, did I manufacture it and therefore must engrave it?

Thanks for any and all responses. I've tried searching and doing my due diligence but keep seeing conflicting answers.

Thanks for the fast response!! What if I don't want to mark up my receiver with my specific trust name for the sake of resale potential? Would I have to give the receiver back to the FFL I bought it from and let him hold it, with the upper, until a Form 4 is submitted and comes back? Or does that require additional engraving as well? It already has his manufacturing brand's name on it.

Wait, the manufacturer of the lower is the FFL that sold it to me. However, he only sold me the lower to register as an SBR and to then come back to buy the upper. Does that mean the manufacturer's name, city, and serial numbers, who is also the FFL, can be used and engraving is not needed?

Only if he is an SOT and he "makes" it into an SBR by attaching the short upper.  But, seeing as how he's already transferred the lower to you on a 4473 as a Title 1 lower means that's probably not going to fly.

I'm no expert in NFA and firearm manufacturing minutia, but for him to transfer it to you as a "factory" SBR you'd have to transfer it back to him, have him make the SBR under his FFL and SOT, and then transfer it back to you on a Form 4.  That's the only way I can see you avoiding the engraving (which really shouldn't be an issue).