Regarding the origins of certain NOS parts, I bought quantities of NOS handlebars and rims from Memory Lane Classics in Bowling Green OH, that was in the early 2000's, all gone now, and don't know where they got them from, but you could ask them.
"Day & Zimmermann, Inc., a Maryland corporation, operates a plant at Cressona, Pennsylvania, where it is engaged in the reclamation, repair, and salvage of ordnance materiel which is sent to the plant from overseas and from various points within the United States.
The plant is owned by the Defense Plants Corporation and is leased to the Company. At peak production the Cressona plant processes in excess of 100,000 tons of material weekly. This material is received almost entirely from sources outside the Commonwealth of Pennsylvania, and, after processing, is shipped almost entirely to points outside that State."
They apear to be the same as G519 pedals, except not painted green. Very nice original condition.
Yeah, I know that was obvious, sorry!
If I had to guess, I would say early 1944. I've had a quick look, and can find other makes/types of blackout pedal bing used on civilian bikes at this point, but not these.
It is thought that the last contract for Westfield G519 was cancelled fairly early into the run, and I suspect parts like these from an outside contractor would need to be ordered in advance of the main production starting, so, in the event of a cancellation, there would be an overrun. It is possible that these are from that. But it is guesswork on my part, I have little evidence.