Just got my LPK from J&T (in just 3 days, BTW). I ordered a short buttstock screw for an A1 stock but I think the one they sent is too long--it's 1.088" and definitely goes into the tube where the buffer will hit it. Could this possibly be right?

The A1 screw is a stubby little thing.  I just checked one and it is .575".

Your suspisions are correct. They sent you an A2 screw.  The A1 screw is .570 (give or take a few thou) long.  Either send it back or cut the one they sent.

Just 'Dremel' 5/8" off of it.  

I'm not sending it back at my expense when they already charged me $9.25 shipping.

I just found out about the Industry forum and posted a question to them about it there. Let's see what they do to make it right.  So far everything else in the kit looks great, and their shipping speed was tremendous. I mentioned when I called them that they were getting business because of good things posted about their LPKs here on ARFCOM.