67 Fury power brake “filter” and push rod?

1967 Fury 4 wheel power drums.

I'm replacing the mater cylinder and the service manual shows a filter sandwiched in the piece that goes between the MC and booster. I can't find replacement sold so is it critical? Or DIY some foam into a makeshift filter?

The MC came with a boot for the push rod. It also has a rubber bushing/gasket that I didn't see come off the MC I removed. The instructions make no mention of it. Any idea if it's even used on my 1967? See pic with red circle....

67 Fury power brake "filter" and push rod?
Author: W4UWC