Go ahead and find one, as they do want to know when you're leaving the hospital. But also know that not all peds go to all hospitals to check out a baby. For instance, I'm going to pick a pediatrician that won't go to my hospital, simply because I picked a hospital in the city right across the river. It's just as fast to get to that hospital for me, as it is to get to one in my city, because it's all interstate rather than dealing with city traffic, but it's not technically in my "area". The hospital has a few pediatricians though that come do the initial checks for your baby though, if you haven't picked one that comes to the hospital.
My OB has actually asked me a couple of times already if I've chosen one, and wants to put it in my notes once I do.