If the hole saw is the right size, you can drill out a piece of wood the right thickness (something that is non conductive).
When that bakerlite eventually breaks, sparks are going to fly.
I broke the bakerlite spacer a few years ago on my alternator. Told you can't buy them anymore, unless you buy the whole alternator.
I was able to get one though.
This only if you can't buy one. Back up plan.
Making your own non conductive washer spacer will save you a lot electrical damage when it eventually breaks.
Preventative medicine.