Oh great apparatus gurus, what is the correct beacon color for this vintage Mack made by Corgi?

http://www.legeros.com/toys/gallery/corgi-1-50-mack-b-baltic.jpg

It's lettered for Baltic (CT?), and I cannot imagine that blue is the correct color.

The packaging shows a clear beacon, which may have been the prototype design.

I've subsequently bashed the model using a Sharpie marker to paint the molded fire helmets yellow, and am ready to (attempt to) correct the beacon.

mjl