Yes my friend got one of those newer Yobo FC systems, and I noticed the buttons are solid plastic instead of transparent like the older ones. It more resembles the RES. As for whether or not it uses the newer NOAC, I can't say as I have no point of reference to compare to. The main difference between the older and newer NOAC from what I've heard is that the audio emulation is better, but like I said, mine has heavily distorted audio. My friend's doesn't, so I'm pretty confident my RES is defective. His Yobo FC had messed up video though, so it seems one or the other has to be defective.
I might buy the RES again, this time from SAG, that way at least I have the 30 day return policy to fall back on if something's wrong with it. My first one I got from eBay. I'm hesitant though because after getting a new 72-pin connector, my old NES is working beautifully, so it's almost completely pointless now.