Welcome to Pinside - I looked up your game on ipbd.org and looks like a beauty. For the backglass, the two reproducers that specialize in em, Shay Arcade Group and Ron Webb, I did not see your title available but you should still contact them. You can get your actual bg restored at http://bgresto.com. For the broken play meter mech, try pinball resource, also on the web.

If you post the snippet of the schematic for bonus score reset, you'll get help reading the circuit. Fixing lots of scoring issues can often be resolved by cleaning the associated stepper units and there are lots of posts here for accomplishing that. The stepper units get gummed up over time and they have to be cleaned to move freely and the wiper blades rivet contacts also need cleaning/polishing.

Welcome to Pinside.
That's a pretty scarce game.
I don't think I've ever seen one, and I've been around pinball machines for a long time.
I can't imagine that the bonus doesn't reset at the start of the game. Normally, is it collected after each ball drains?

How about finding the bonus stepper unit and inspecting how it works? If there is only one coil and it steps forward only, then the luck of a high value could land on either player. Gottlieb did that later, on Groovy and Crescendo, for example.
.................David Marston