I bought a manual 500 on eBay recently for the fairly high price of $32, but it seems like it was worth it!
www.ebay.com/itm/132086243798
I could see from the later handset cord that it was obviously refurbed at some point. What got me interested was the mystery color underneath the black paint on the dial blank. I was so curious that I ended up buying the phone! ::) At first, I thought it might be Yellow, but I became disappointed after I somehow convinced myself that it was really faded Beige. I was also unsure of whether it was a 95B or 95C, and was really hoping for a B.
My hopes were right, it's a Yellow 95B! Not a color you see very often on a manual phone! :) It's ABS, but has markings on the back similar to my 95A that my other 95B blank doesn't have, so I'm guessing it's early '60s.