Since there's been an update, I figure it's a good time to share what we have found.
The proper name for this type of siren is 2 C 2 1/2 T (rolls right off the tongue, right?). Here's a picture of one I was able to get an ID tag photo of, another 12-port model like this.
- Darley 2C 1.JPG (1.59 MiB) Viewed 6720 times
- Darley 2C 2.png (936.9 KiB) Viewed 6720 times
There are also a few slightly different model names for the single-phase variants based on horsepower that we're still trying to figure out...
Great to hear it has been hooked back up! Please do share a video of it running if you can!