First, let say this about the Sport II, it is a fine rifle and I enjoy mine. I have a POF Purtian piston that if it is not top tier, it doesn't miss by much and they both shot a whole lot better than I can.
A couple of things I did do to my Sport II was add a Magpul front hand guard, a Magpul stock and a Magpul grip, all in FDE. I did change The charging handle to a Bravo Company and BCG to a Nc WMD both of which I had from a previous rifle that had very few rounds through it. These things I did because I wanted to,not because the rifle needed them.
Mil spec is a miss used term anymore. The Sport is not, nor is it intended to be "Mil spec". The "enhancements" I added was done simply because I had some parts from the M&P I traded for the POF and I happen to like the Magpul stock, grip and front hand guard.