Sam, absolutely. I couldn’t stand that story from the first moment I heard it. There are countless stories of Gedolim where a dream affected their decision.
The Gemara only uses “Divrei Chalomos Lo Maalin Velo Moridin” in a Halachic context — that even if the Baal Hachalomos (obviously they believed there is one) tells you that certain money belongs to a certain person, and even if he gives you a Siman that proves correct, it does not go to that person.
Other than that there are many instances of Achzu Lei Bechalma.