Absolutely - I've even seen that sort of thing annotated in Find-A-Grave from time to time. Where the headstone reads one date, the description is different, and there's an explanation below as to why the headstone was incorrect.
On the flip side, I've also seen records that were just wrong, and after looking at the photo, it's clear they misread things. In doing the Cemeteries project, I've corrected all number of errors out there after photographing the headstone and matching it to a record that was obviously done incorrectly. I do my best to try to fix those problems as I come across them (if I can).