I don’t know if this is useful, but this site, https://www.reranch.com/ sells nitrocellulose lacquer in aerosol cans. These paints are sold for refinishing guitars, but I think they may be very close to old style automotive paint. The colors offered match the colors of vintage Fender, et al, guitars, which are often the same colors used by car makers in the 50’s.
I used their products to refinish a Stratocaster body, and once the wood was prepped it was a series of many coats of lacquer and wet sanding, followed by coats of clear coat and wet sanding. It took some time but was economical and the end result was very good. If they have a color that works it might be an economical fix.