Wiring for the J22 version (older, not what you have).
Exploded view for the older style, note the power supply in the middle. Also the parts list does not list colored domes for the strobes at this stage.
More modern version like what you have (smaller potted power supply).
I'm pretty sure they used this dome, which came in all colors. They were WAY more common in amber.
They were more commonly sold via target tech/amber markets
This was the tall dome Federal used from 1999-2005-ish (from what I can find), it was threaded at the bottom. It was an amber product 95% of the time. So while there were all colors of domes, they are far more common in amber and clear.
So yes, you could swap in some colored domes, they just aren't common. Keep a look out for misc strobe domes with a threaded bottom on eBay and other sites, they aren't usually listed as Federal as the sellers usually have no idea who made them. Also, Federal wasn't the only company with threaded domes so be careful. Your plan is possible....