The bumper you can cut out of a piece of old tire tread. I thought I bought one from Jim Carter, but don't see them there now. As far as the guide, I think that's just a washer.
[on edit] The FAM shows the "guide" as a square piece with a hole for the shaft. I think that might be the seal that goes in the pocket on the brace for the parking brake assembly. JC has those made of felt and leather.
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