I run across questions like this in all kinds of places every so often; and Ive never seen an place mentioned to go to. It seems you have to inlet one yourself if you cant find a replacement at someplace like 'GunParts', etc., or get lucky at a gunshow on the same model that is shot loose and for parts.
BTW, a lot of old guns have a name on them that is not who made them, but just who sold them. Finding the real maker (to ease your parts search) can take some research.