Yeah, in my family no one ever made a distinction. You'd look someone up in the yellow pages, they were all in the same stack, and only a prig would correct you, "you mean, look him up in the White Pages".
In the US, we said "the phone book" to be generic. The specific books were always specific.
As in "Did you look him up in the phone book?" which might be answered "I couldn't find him in the White Pages, but the phone's probably in his mom's name and I think she has a different last name, so that might be why. I think she has a business but I don't even know what industry so the Yellow Pages don't help here."
