Does anyone know of anyone reproducing the threaded tank filler caps that say "GAS" and "OIL" stamped into the top of the cap? i have seen a few of these caps in rough condition, and would like to have a nice pair for my '27. The caps i have seen fit the '27 tank Were these caps produced by the factory and fitted to bikes coming off the assembly line, or were they an accessory? If an assembly line part, what years were these caps fitted? Thanks in advance.