The skull with the bullethole

When they brought out that fossilized skull with the bullethole in it I was wondering if there was actually anyway to know WHEN a bullethole was made?

I mean if they had the bullet from whenever the thing was killed and it dated as being 150,000 years old or something like that then they might have had an argument.

But anybody could steal an old skull from a museum (or if they are actual archeologists maybe they found it) and then shot it with a modern gun and how could you know the difference?

I admit it sounds like a cool science fiction story though, modern man takes a hunting expedition back to the stone age and kills a sabre tooth tiger and then hundreds of thousands of years later the fossilized remains are found, along with his discarded Smith and Wesson?

Although I think it's already been done before, can't remember the title of the short story and it might have been about hunting dinosaurs too.