Help naming that siren speaker

I recently purchased a 1989 Maxim Tractor Drawn Aerial Ladder which formerly served the New Bedford Fire Department in Mass. I am trying to bring the truck back to its original self or at least as close as possible,

For the longest time the truck operated a single electronic siren speaker on the driver side front bumper. After looking at whatever photos I could find I believed it was a Federal Signal CP100 but now I’m starting to doubt myself and I was hoping some one here may have a more definitive answer: any help would be amazing. Thanks again guys and gals

 

[tsquale]

It appears to have a flat back vs the more rounded CP series. I know Atlas sound made one like that. There are likely others.

Here is an Atlas example: https://www.worthpoint.com/worthopedia/vintage-atlas-sound-chrome-fire-truck-405300274