Ned, It's my understanding that the the 51 and 61 should use the same stock.
You may need to check and see what make revolver you have, Is it Pietta , Uberti , EMF or what??? Then you can ask one of the dealers if they have one for your gun. Hope this helps, Mike
PS Cabelas did carry one for the Piettas but I don't know if they still do. Also you may try Dixie and many others.