They look identical to me but then again Mary Kate and Ashley aren't identical twins so who knows!
and re: leaving them in the crib. That's never sat right with me. I have twins and they used to be fairly happy alone in the cribs for a while and probably would've been happy to sit for an hour, but I would've never left them for that long. I would leave them for about 30 minutes, tops. Just long enough for me to make a coffee and get their bottles/breakfast ready without babies at my ankles.
I just can't stand the way she starts filming while the babies are SCREAMING. I know they're fine, but why? Just give them their bottles off camera for once.