I'd definitely raise. You said the rake was already capped. You're sure nobody has a pocket pair higher than 5. Are you sure nobody has the 4th 5? The way you explained it, it doesn't sound like they do so you may as well raise for the reasons you stated. But Ii don't see anybody folding to your raise for that matter either. And why were the 2 folds key?
I'd raise it anyway. I've seem people give up their share because some body represented a better hand by raising. Not a good move, but, it happens. When in doubt, raise. Representing works.