Toilet Issues

I'm restoring an old 1971 Winnebago Brave and have had a hell of a time trying to get the toilet to work. It's a Traveler 910 toilet. When I first hooked my motorhome up to a water hookup I noticed the toilet valve was leaking from the valve and that the bowl also didn't hold water. I ordered a new valve and gasket. I went to install both today and noticed that ever with the valve and actuating arm off that my toilet ball still didn't want to close. After pulling the toilet out I noticed scrapes on both the toilet ball and the throat (I believe that's what it's called). Turns out the ball is contacting the throat of the toilet making it hard to close. Would a new ball fix this or is this toilet a lost cause?

I searched but haven't found any cases where the ball scratched up the throat of the toilet. After all this is it even worth fixing or should I just buy a new dometic toilet for $100? Thanks for any input!