Steve, here's a pic I pulled off ebay to use for general reference purposes. The aluminum ends probably would have had a "dull" polish to them. No where near as shiny as the carb covers or the outermost cylinder head fins had.
The series of metal bands towards the center appear to have been cadmium plated originally.
These are just my thoughts based on what little I've seen of these at this point. I'll let the experts make any corrections as necessary.
