Actually it's not. The original RS4 had a silver chassis, and the RS4 2 had purple as well as all other following RS4s, not blue. Also, I believe all RS4s had c hub suspensions not pivot ball. The upper deck is totally different as is the fuel tank. The shock towers are also completely different. I could go on. Unfortunately I am not sure what either one is, but I can tell you it's not an RS4.
Ahh good catch on the pivot balls. I figured it was a GPM chassis looking at those poopy silver phillips screws. The front top is sectiones like an RS4....More digging required.