Chuck,
It was zinc but I worked very closely with my plater on the cover as well as the base plate to insure that it was not a bright zinc. The cover turned out
exactly the way a mint condition original I had looked and I was very pleased. He knew about the bushing and stated that nothing he was doing to the housing would effect the bronze so we left it alone.
The decals I have had around for years and I honestly don't recall where I got them from They could have been Paragons, I don't know. Seems like I recall buying a bunch of these while at a Chevrolet National show in Tinley Park, IL about 6 years ago from a vendor who was there selling his w/w restoration service.
I was making a joke about doing these ourselves as they are not for the faint of heart and can be nerve racking and some special tools are needed. There are a TON of parts that one needs to keep track of just like doing a steering column.
I do all my own rebuilds simply because I am too impatient to wait for someone else and I can control the detail level.
Rick