Yeah, go for it.
How you do depends on your opponent's skills, and you being a rising 4.5 or a falling 4.5.
Do you have weapons? Are you consistent only?
You'll get pummelled as said, most likely, but you can draw some duffers too.
I wonder if you get any points for going a few rounds in Q's? In 1977 and '78, I went 4 rounds in a Q as a B or 4.5 player, lefty, 2hbh, big serve, quick at net.