Those great diagrams of LMC is why I bought so much from them. Five years after disassembling my bolt, I needed that catalog to know what goes where.
That stuff you are wondering about are anti-squeak material. All I ever got was like heavy black paper and not to last too long as anti squeakers. I went to Home Depot and bought a piece of the material that roofers use with a propane torch to seal a roof. I traced the shape from the black paper. It is about 1/8 inch thick and is perfect for what I need. I doesn't seem to affect the sheet metal fit up front and will certainly do the trick. You might also look at asphalt shingles.


~Jim