Yes can ask and they will tell you that you're on the list, but...
Processing (and priority) of the wait list seems to be haphazard at best.
I've been told that I'm on the list, but when I get a seat alert from EF, I always call the EXP line. In every case, the agent processed my upgrade based on my proactive phone call. It may have have been coincidence, but I doubt I was at the top of the wait list each time I called. And others have noted similar success.
FWIW, in all cases, these were for domestic travel.