Question: Which is preferable for large prints, glossy or matte? Or does it matter.

Yesterday, I dropped a 30x40 Fuji Crystal Archive glossy print off at the framer. He told me that he couldn't guarantee the mounting since I had it printed as glossy. He says matte is preferable for such a size. What is the problems associated with mounting and framing a print of this size? This is the first print I have done of this size.