yes, but not directly. looking at someone's muselist will tell you what kinds of things they like writing/reading about, but from there, you have to extrapolate a little. that common trait or trope or plot element might be direct wish fulfillment, but it also might be fascination with something they don't personally relate to or it might be a catharsis thing or any number of other reasons people like certain things in fiction.

another telling thing is not just the characters they play, but the kinds of plots they usually run or cr they usually have. same applies there.

all the nicest people ooc i've known have been people who played really assholish characters from a position of removed, analytic interest, and all the most irritating have been people who play near-flawless hero characters with lots of personal emotional investment and only want positive threads and cr.