Jeff,
When I painted my SHELL 36B Twin [with homemade showcase]14yrs ago. There were few [if any] parts being made for it. I casted many parts useing BONDO & RESIN mixed. I used a metal plate with machine bolts for the pices that needed tobe attached like originals. Then after pouring the mixture into the mould, I would lay the metal plate on top of it.
VERY few people know what parts are HOMEMADE.
The middle adv. top is made of WOOD. Because I collect 36B tops, I could replace it with an original. BUT, I painted it 14 yrs ago, and trying to match the paint would be nearly impossible.
Dick