I've seen worse condition pistons before on a Mustang I used to drive. Timing chain broke and all of the piston heads had nice intake valve notches in them, much worse than your one piston. I put new heads on and never had a problem. I agree, you're lucky.
My vote is to put new head(s) on and run it until she stops. Good luck.
PSA - It would be nice if people made an attempt while typing to discuss their problems or opinions instead of one long sentence with no punctuation. Maybe I'm cynical, but that really pisses me off. Rant over.
"It's like saying I had a car I got that was painted by the previous owner. I had an accident so painting a car is unsafe." - cykaaro