It's cool.
The hat dropped at the end of the fight, when all the Garlean depopped and the music turned back to normal music, not as a drop from one of the little guys.
We just didn't kill claim or even survive 3 hits from the NMs but we did kill the random level 50s roaming around. We did help attack the magiteck and the nms though, did a little bit of damage.
It's possible that, at event ending, there's a random chance if you participate.
