The holster also fits a Colt Official Police 5". Holsters of that era were not particularly tight fitting and most will fit a couple different guns.
As far as getting the codes, I have a couple old leather brochures that I picked up off FleaBay. They were cheap and come in handy now and then. Someone had scanned a fit chart and posted it here but I haven't seen it since the move. I don't know if it's still here or not.
Bob