Quote from American Marine diary about tracers during vietnam:
0200 hours - Heavier fire coming in. Never had seen green tracers used against us. In a way, kind of pretty to look at, red tracers going out and green coming in; deadly green.
I really wish these sources could be a bit better but honestly information on this is surprisingly weak. If anyone reading this happens to have fought in Vietnam and can confirm that american rounds are red and VC rounds were green, that would be wonderful.
(block quote above is from SciFi StackExchange answer to star-wars question What is the significance of the reversed colours of imperial and rebellion lasers compared to lightsabres?)
Is there some historical confirmation to this assumption about tracer color being uniformly consistent red/green on both sides?