One of my best "Old School AR" is still my Kokusai CAR15 but since we are into new tech My Systema M723 PTW was the bomb till it died long time ago and has been replaced with my FCC XM177, the finish is so nice that I went and splurge on a VN era RS foregrip, stock and the RS triangle sight and unfortunately I loved it so much that it is my one and only shelf queen she is still a virgin never fired, not even violated by a battery.
As for G&P they do make a very nice CAR15, XM177 and a VNM16A1 which I have owned in the past.