Miami's- they are completely different hand signals.
This link shows how different the two schools sign is, and I do beleive I have heard Utah had been throwing it up well before Miami anyway.
http://farm3.static.flickr.com/2540/3711782880_0523c9f337.jpg
so as shown, Utahs "U" hand sign are the two thumbs joined together, and dropping all fingers but the 2 pointer fingers.
Miami's "U" signal- simply connecting both thumbs together making a large U with both hands
Clearly different hand signals