I ran into a similar situation 4 or 5 years ago on an LB7. It was actually worse then this. The owner had an injector stick open and one point on a road trip, and since then had severely overheated it due to blown head gaskets.
He wouldn't let me repair it. So against my better judgment I put everything back together and put the damage I had found, and "repair declined" on the ticket.
To my surprise the truck started and ran fine, even in the cold. Doesn't use oil. And as far as I know is still running today. I couldn't believe it survived the test drive honestly. Sometimes things like this will blow your mind how long it lasts.
I wouldn't count on it however.......
It crossed my mind that this damage could have occurred 30k miles ago when the injectors went out. Or the shop that did the work could have dropped something in the cylinder who knows. I just got the truck.
Im going to run the hell out of it and see what happens. If I see 300 lbs on compression gauge ill stop driving it