Good point re blind. Will service cam pivot for sure thank you.I don't think so? I think all the sump plate bolt holes are blind? That means no oil could leak out of them unless the section of gasket surrounding them was bad. Added washers are just more parts to fool with, lol.
When you replace the brake shoes, service the cam pivot in the brake plate. That drying out is the major cause of drum brake squeal and screeching. Details are here starting with post #3 .....
https://www.xs650.com/threads/how-difficult-is-it-to-replace-the-rear-drum-brakes.25632/