Well, I decided I am going to bite the bullet and get the SBR done.  I have a Spikes lower with a buffer tube and upper with no barrel.  I am going to send off to get engraved prior to submitting the form to be certain that if there are any errors, I don't have an application in process.  

The configuration I am looking at will likely cover any caliber markings on the barrel.  

Do I get the upper engraved with the caliber (the lower is marked "multi")?

Do I put my full middle name, or is my middle initial acceptable?  I know it says the city abbreviations is OK, which I plan to do, but not sure about the name.

Thanks

Your barrel is most likely already marked with caliber.

Middle intitial OK.

My barrel markings were also hidden well enough that I just had Tarheel engrave caliber along with my other info when I SBR'd. It was actually sort of amusing to me that my CMMG dedicated 9mm lower didn't have a caliber marked...