Quick reminder and absolutely being pedantic, but "M-5" isn't a name Sterling ever used, they're just Model Ms. He joined before many of us were even born, I think he gets a pass... Wasn't sure much would come from this thread, glad to hear it's still around. I wouldn't skip out on a remi...
Maybe 15 years ago - just going from loose memory - there were known to be two Chrysler-Bells still in China that the US sent over there. The only two known to remain. One had since been fitted with a large electric motor, and the other had a replacement engine that was different from the original....
This is super cool and totally intriguing. Do you have any photos of any of the sirens? Edit: By the way, the unconfirmed P-15 marker in NY has a suspicious P-15 shaped blob down and to the left: https://www.google.com/maps/place/Lake+Arrowhead/@40.960244,-72.7718275,37m/data=!3m1!1e3!4m6!3m5!1s0x8...