Can't remember have I purchased one Wood Cross in the past (I think I just might), but I had that in inventory. Is it why I got the Stoney Broke achievement now without buying a gravestone today? To be more exact, I got the achievement after shooting one golden bazooka in Shop's Try me screen, which could indicate that it was a bug. Is it?

The gravestone achievement is new so if you own a gravestone (other than the ones you start with) you will get the achievement when it next checks for achievement completion (such as when you fire a weapon)

Okay, I suspected that, but just wanted to be sure. :)