Keyless chucks are older than most people think, they are described as a 'new' feature for electric drills in 1929. However, the design internally is different for those than for the recent ones that are based on the Jacobs chuck (3 fingers and a ring gear), many of the early ones were collet designs (the adjusting collar screws in and clamps wedged fingers into the bit)
The Stanley handyman' series became widely advertised just after WWII, probably due to the large do-it-yourself home-workshop trend that was becoming widespread at the time. Your drill appears to be based on the keyed chuck model 04, which otherwise looks identical.
My guess would be that it's from the early 50's, and probably not much after that. There is no mention that I can find for advertising for it, I'm wondering if it didn't work out so well (perhaps too $$?)
The second wave of keyless designs (Jacobs) is from the 60's-70's and more or less comes at the time of the first cordless drills, I don't think that drill is that recent...
(Black and decker claims the first cordless, in '61, but they were way late with the keyless chuck)