I don't know how popular these black and white C5+'s were, but the dovetail that was made for the bottom of them for mounting is now just about impossible to find. It was a regular width, I think (even back then?), but only about 4" long. The hard part to duplicate today is the four hole pattern for attaching the dovetail. That ain't normal. The holes are a square 1" on a side. The holes are also not straight up and down, but tilted to be tangent to the curve of the body of the telescope. Tricky.
When I bought the scope it came with two large rings for mounting. That looked about as elegant as I do. I had a no-name Vixen bar that came mounted to the C8 that I got in Arizona that got replaced by a set of forks, a wedge and a tripod. After failing to find the real thing in all the usual places I had my local machinist/magician chop a piece out of the Vixen bar and drill the holes. I could have done it, but you wouldn't have been able to get all four screws in, and the telescope wouldn't have been pointing straight ahead if you did. This worked out much better.