That’s a tough call on how long AE made that phone. Would think the induction coil handset would have been discontinued by the 1940’s but AE typically would make anything that someone would buy. So, if these were a popular item for stock exchanges maybe they just kept making them if orders came in. I never saw them here and I had the opportunity to scavenge one of the Vancouver stock exchange right after they moved to a new building somewhere around 1980. AE 43A spacesavers and flush mounted call director keystrips as it was all AE 10A2 (1A2).