I just bought a 4x5 RB Super D, serial number 416991. It's in fair shape, a bit musty, a few mold marks on the case, and a bit of fungus on the lens, but the aperture and shutter both work well. I was surprised to find a Graflok back on the camera; I initially pulled out my Grafmatic 1168 to check the fit, but it was too wide; a 1268 fit perfectly.

Can someone with the serial number book tell me anything about this camera?

416991 is in a block of 1,000 4x5 RB Super D serial numbers 416341 - 417339 issued 2/6/1947. I think these were the first Super Ds made. The next block of 4x5 RB Super D serial numbers was issued 9/21/1947.

The Graflok back has to be a retrofit, since it was introduced in 1949.

Thanks, Dan. I figured it was one of the early ones.