UPDATE: I cleaned the vise today and really scrutinized it for markings. Using a strong light, magnifying glass, and the zoom function on my wife's phone camera, I can faintly make out what appears to be "No.006" and then below it ' "PAxxxxxEN" ' (the x's stand for unreadable letters). From this, I gather that it's a Palmgren vise.
Thanks again to all who helped.
Harold