Rick,
I asked the same question some time back and got nowhere. I think someone sent me a PM about making a custom rig if I could send him a tracing. Never followed up on it and eventually went back to just irons on my 22/45. Switched out the rear to the "one ragged hole" aperture sight and couldn't be happier. I do almost as good at 25 with it as I did with a dot and it's a whole lot handier package.