The lightbars, by their very shape, are actually modelled by NNICO last I checked. RK1000 simply did the Freedom variant and the length variants of the lightbars, so both would need to be credited. The model itself is a bit too curvy compared to the real lightbar, which is why the shading on it makes colors look cartoonish to some people. The real ones look bulkier and squarer to my eyes at least. In Em4 at least, none of those internal model bits like the LED modules matter, nor should they be modelled due to how Em4's top down view does not really allow you to see stuff up close without sacrificing your ability to respond to calls.
For the colors, the ones being used rn would be a bit too vibrant, especially given Em4's weird light system that makes everything brighter than what you would see in your image editor. A more realistic color IMO would be a darker, more maroon red, and a more dirty looking blue.
FWIW, EmC and Flnn have gotten the module setup, layouts and lights correct. This little change may improve the appearance further, but will warrant the reworking of all existing lightbars.