I wouldn't expect 60k rounds to make the grip safety more "sensitive"? Although there is little wear to be expected from the grip safety rubbing on the trigger bow, any wear would make the grip safety less likely to function, not make it more sensitive to grip. I'd take it apart, and look for a burr on the trigger bow, or something else that has changed the relationship of the safety and trigger.
You're sure the grip safety is the problem? Just for giggles, you might check that the disconnector is resetting correctly.