The records from the 1930s "suggest" any ".357" with a registration number would be issued a certificate if the owner requested one, regardless if the gun was shipped with a postcard to request the certificate or not. The certificate was a lifetime guarantee for the revolver. I also found a case where a Marine requested a certificate for a "non-registered" Magnum and S&W, per their letter, agreed to send him one.

As with all things S&W, "Never say Never".

Bill