Definitely possible. I've seen F. subpolita queens from the Angeles Oaks (workers are usually all black or dark brown, queens browner) but they are much darker than the bright hues from the one on this post. They are also smaller. Subpolies aren't very large (about F. francoeuri queen size).
The one found on this thread was relatively large, it's also what is throwing me off. Here's is the inat observation. Literally exact same trail. Look at the elevation. Very high.
https://www.inatural...ations/29430032
There seem to be similar ones in the San Bernadino mountains. https://www.inatural...ations/29588113
That isn't it, however, a user on here found ones that were identical to yours in a similar location. My guess is that they are indeed subpolita, as they seem to be in incredibly variable species.