Yeah i noticed that on a couple of cars prepatch but i dunno if they fixed it on the patch as i havnt played since i bought Skyrim really. Cars i noticed it on was the 350z and on a VW(i forget which one.)
Early after the game's release, I had a hell of an online Cycled Production race in an Escort Cosworth because of this issue! I figured it was because the car was RHD, and a lazy mistake. But it could be a random glitch too.
Haven't seen it again, but I haven't driven the Cosworth again either.
Oh boy...I just tried the Escort RS Cosworth again. It's still wrong post-patch, and stranger than I thought.
The rear view mirror and driver's-side mirror are backwards, like mini versions of the normal "look back" view...but the passenger-side mirror is correct.
Edit: Scirocco R -- Rear view mirror is backwards, side mirrors fine.
350Z -- Rear view backwards, side mirrors fine.
I'm not sure where else to begin to look. This is pretty strange though, and easy to check in Free Play -- Bernese Alps Festival (A button, A button, A button...) has yellow "Pirelli" and red "Simpson" banners on each side of the track, visible in your mirrors from starting line.