I'm jealous - wanting a bowler forever. Probably a good thing I have not found one as I have nowhere to put it.
If you are new to EM's, read this first.. http://www.pinrepair.com/em/
Tons of important info & repair tips. Go slow & tackle one thing at a time. Don't go ripping it all into a million small parts.
A SCHEMATIC would be a must if you don't have one. I use a dremel with a wire brush for EM switch contact cleaning, but each have their own methods. Looking forward to this restore blog!
Check out this guy's website, he might have parts for you https://www.stl-bb.com/
Oh, & have fun with all of those score reels, you will be able to take one apart & put it back together blindfolded before you are done.