Lookin' good! If you can get a hold of one try an AFG on it. It fixed a lot of how fat the pump felt to me. I noticed the newer ones have a lower profile 1 piece pump on them.
I'm kind of curious to see the difference between the large caliber PAR upper and the dimensionally closest AR10 variant upper and how close of a fit they are, as the rear of the .308 PAR lower is "truer" to the original than the .223 version. From what I can see the angle at the back is slightly different than the standard DPMS or AR10, the pin location is probably different, and there is no hole for the buffer tube. Not sure what else I could be missing but unlike the .223 those differences could be "fixed" with a little machine work.