It's kinda story locked, but there are still things you can do with it.
If you find the headstone, it's similar to the two ruined Estates in the swamps in that you have the option to repair or destroy the headstone. The consequences for what you do (if anything) become relevant during the second Haunt, and some other things become available after completing the second Haunt. The state of it will also be relevant in Act 3.