Newsom is the only high level government official I know that got a J&J shot, rather than an mRNA one. I believe he received the 1-dose (at the time) J&J in order to encourage others to use that one.
All the others (Biden, Harris and even Trump) received the Pfizer.
Got to be truthful, the fact that the most high level officials got the Pfizer vaccine played a role in my choosing the Pfizer vaccine for myself.