The Siren Board

I've been wondering if the Sterling that Cole Camp MO has, if it is a M-5 or M-10. I'm still kind of new to sirens. Also, if anyone knows how old it is that also would be great
Google Mapshttps://www.google.com/maps/@38.4617225,-93.203 ... 312!8i6656

The general consensus is that it's a M-5. I dont know exactly how old it is, but my guess is that it's from the 1930s or 1940s.

Um, by the shape of that, that's an even divide between both. I'm leaning toward M5 as well because of the base, but I can't figure this one out.