My initial impression is that it's way off, but that's just compared to other models I've seen, I dont model the livery. After doing a google image search, the colors of the subject S4 do indeed look closer to prototypical IMO.
That doesn't really matter though when every other model seems to use darker grey and maroon, even previous models from the same manufacturer. Lionel should have stuck with what has been made in the past assuming they'd be run/displayed together. Just my opinion which ain't worth much! Haha