I have a question about the Ruins of Alph. How do I unlock the final two Unown?

I have caught all 26 of the regular Unown, and my Unown report has them all in order. Supposedly, the ? and ! Unown are supposed to show up in the entrance hall to the ruins. However, they haven't.

(If the problem is that you have to access all four of the treasure rooms, I haven't done that yet. I don't have Ho-oh yet. But if this is the case, I'd like to know.)