I have one of these sets also. Only thing is the one thing of value here was stolen back in the late 60s early 70s.
I have the SAA .45 one. Just the gun was stolen i still have the cylynders and the commerative coins that it came with. And all the paper work that it came with.
The cylinders have matching serial numbers the the missing gun PE431E
the medals were made by the US mint. And this was actually issued by The Pony Express History and Art Gallery in San Rafael. Waddell's son open this museum and got deal going with Colt to make these. these came with some interesting paperwork and matching numbered coins.
I found an add online here : http://www.cbgxtra.com/Portals/6/Iss..._031105_46.htm
That lists on at $1800+ but i don't know how old the add is and I believe that includes the pony express books too.
I'd kill to find my matching # Colt