I don’t really have an opinion/answer to this. However, since I am fascinated by fossils, here is a project that appears to deal with it well - https://inaturalist.ca/projects/16560. Old, or fossil specimens are valuable, as they provide some evidence that species x was in location y at a point in time. I feel a note about the specimen should be enough to explain the observation. It may not be recent, but often (like the mountain lion) it can be identified.
However, as I’ve said before, I’m sort of lackadaisical about the ‘rules’.