They are called Jones plugs and are still being produced. I think the size you have there is the 400 series which has been replaced by the similar 2400 series. I don't think they were really intended to mate with standard NEMA wall plugs, but hey, if they fit snugly, why not?
http://www.cinch.com/products/misc-c...angle-bracket/
BTW, the polarization that is referred to in the spec sheet is the extra pin(s) and holes which prevent the whole plug from being inserted backwards. If you use them as an AC outlet, they are indeed non-polarized.