It could date back as early as the 50s, continued into the 60s or 70s. The motor and handle look near identical to the motor and handle on their Model 909 Allsaw, which I believe was first made in the 1950s, and which would have been a great tool if only they hadn't decided to use a proprietary size of blade shank (and if they'd beefed up the splines on the motor shaft; I once twisted the splines right off an Allsaw, cutting overhead and jamming the blade).
That's a fairly cool design, with the ramped front shoe for depth of cut. And, unlike some of the power planes of that period, it's not limited to edge planing - though I hope it did originally come with a fence, since edge planing is where a power plane really shines (see Northwoods' comment about fitting doors). With a good power plane, you can screw up a door nearly instantly.
