[Hallicrafters] SX-100 help needed

[Ed]

I'm putting my SX-100 back together after a long time in pieces and I have
come across two bushings/"O" rings that I don't remember where they belong
but I think, behind control knobs. They are plastic 5/8"od,
1/2"id, and 1/8" thick. I can send photos if someone needs them.
My guess is the main tuning knobs but I'm not certain, does anyone know?
Thanks,
Ed-KV5I