He might have gotten into a little fender bender and replaced the grille. Or maybe he removed the V8 badge to try to reduce his street value. Not kidding, I saw a thread on the RAV4 forums that some guy wanted to remove his V6 badge on the front grille in hopes that it wont be a target for theft. Basically just worry about whats under the hood and make sure it is mechanically healthy.
I'm pretty sure all V8s came with the little symbol in the grille, but there very easy to remove so yah never know what the previous owner did. But it could also be that it got in a front end collision and they didn't replace it, just be cautious