A brand new rifle in my experience never shoots MOA out of the box... gotta break it in. Others might have a different opinion, but to me the biggest difference is comparing a NIB rifle to a rifle you have hammered 1000 rounds out of. (familiarity, barrel break in, comfort and etc will all affect your results)
The other norcs pictured in this thread look really nice, and for the cost savings of the NORC you can pretty much outfit your AR15 to the tits. Its not like we will ever get to use the AR for anything aside from blasting paper so might as well save some cash

and buy the norc then upgrade the trigger and etc to parts you do like.
As for groups I agree you need at least 5-10 shots on target and preferably a try groupings on different days. Two shots in my opinion will not tell you much, and statistically the larger your sample size the more accurate your results are.
My suggests for better comparison
1) break the Norc in before comparing results
2) shoot from a bench with a bag/rest
3) shoot more groups with a variety of ammo on different days
4) shoot from 100 yards (just cause .5" groups at 50 yards don't count
I kid I kid))
Cheers