Last summer both the girls would wake me up around 2 or so wanting out, no they didn't have to potty they just wanted to be out. So I'd leave them out, if they wanted to come in they would let me know, but usually they didn't & just stayed out till I got up then slept all morning long!
Like KYS said, if your yard is safe & secure & Oreo wants to sleep out there I'd let her.