i couldn't find anything either. i'm thinking they may just believe what you list in your AADSAS application and ask you later on in the interview if granted one.
thye want you to have those hours by the time you interview. OU is one of those schools that allows you to send additional stuff after you've already submitted your application.
I cannot tell you if they have changed their policy over the past two dental application cycles, but when I applied two years ago, they did not require it.