I loosely interpret some of these laws
If your bike did not come with turn signals, they dont have to have them in Washington. So yeah, take that as you will. I have looked and not seen what constitutes legal turn signals, but honestly im not worried about it. I dont run mirrors either, and i know thats not legal.
My bike is registered in Oregon since i am a legal residence there- I havent looked at there laws as i dont go there too often, but im sure i will find out what they are if i get pulled over!
Either way, this bike is unique enough that i feel like most turn a blind eye or dont notice discrepancies, and if they do, oh well. I have not had a problem yet!