I agree about the dial being refinished. The watch itself is a legit Longines model. Here is information:
https://vintagewatchresources.com/watches/stop-second-sweep/
gatorcpa
This is one I picked up a year ago. I haven't seen another with a pulsation dial. I am sure they are out there so please share.
Strange one: https://www.watchnet.co.jp/en/item/view/4546
I think that the serial number of 23'484, 40 (Curious Curio) might start with 7'255'xxx.
But 6.996m is 23074 territory. May be a bitsa but then is still the question what the casereference should have been