No, UFC follows the rules of the relevant athletic commission and they only use referees (and judges, and timekeepers, etc.) licensed in that jurisdiction. UFC famously moved a fight from NV to CA because NV wouldn't license Jon Jones to fight after a drug test: https://www.espn.com/mma/story/_/id/25603991/ufc-232-moved-l...

"Unified rules of MMA" were developed at the state athletic commission level (NJ maybe?), but not everywhere implements them: https://www.mmafighting.com/2019/4/16/18358920/abc-survey-at....

The ending of one fight in TX had betting implications because of their odd rules. https://www.mmafighting.com/2022/6/21/23177038/texas-commiss...