Looking in my '44 Chandler catalog, Stanley had a 760 series that is somewhat like it, including the odd little horn. But it's not the same design, based on the stripes and streamline design I'd put it more 50-s'60...[WAG]
Damn if it doesn't have several features that belong on a Parker vise tho....
The anvil, the vertical reinforcment on the back jaw, the bull nose, the lines.....hmm
Not that stanley would ever 'improve' someone elses design or anything...
Edit: It is in the 1958 catalog, assuming it has 3" Jaws, steel, is #766 (cost $13.90 )
(Iron jaws #746)