"Silvertone" was the name used back when you could order Saxophones, Clarinets, and Flutes from the Sears Roebuck catalog. I never heard of a Silvertone recorder, but quite likely they had them.

I think Sears & Sawbuck quit publishing musical instruments and switched to just guitars in their catalogs sometime in the early 1950s or so.

Of course the name may also have been used by others.

John