Apart from the timing rules dictate the order you resolve effects, not the order of the components within the effect.
If you gain 3 tokens simultaneously they all arrive at the same time.
There is a president for multiple assignments with damage cards and damage clicks on squadrons where by they are assigned one at a time, but nothing that says the same about command tokens. Unless I've not seen it in The RRG.
Does it specifically say anywhere in the RRG how multiple command tokens would be gained/assigned?
Well, then they all get discarded.
Because if they happens all at the same time, when you check if you already have a token of this type, the answer is yes.
Edited by WildhornWhen a ship is assigned a command token, if it already has a copy of that command token, it must immediately discard that command token.