I don't think it is KSC, might well be wrong, but it definitely doesn't feel like the stock frame. It feels a lot more like the real steel Glock 19 that I fired in Switzerland - thus VERY nice. The frame feels cold to the touch almost like metal and is very heavy. As for the actual grip, its perfect. Fits very very nicely, however I'd love to see what it feels like with a Hogue on it.
Definitely worth the straight frame instead of the standard one.
Chrissy
edit: Fair enough if its KSC