There is also the gold-plated and .500 silver RCM
Ottawa/Winnipeg medallions, which are listed in Charlton, but I also found out that there is at least a 5th type
This 5th one (antique finish) is interesting - I never have seen or heard of it, I'll update my notes.
The .500 silver one is very, very hard to find - it was issued in a blue case with the other three common types (nickel, bronze and gold-plated). I have only ever seen one (which is in my collection).
By the way, are you aware that I am the person who wrote the exonumia section in the back of that Charlton catalogue a couple years ago?