Like ferg said, I really dont know if this is true or not but there does seem to be some indicators if you watch the pressers and the overall demeanor he displays. Its not overtly evident but overtime there seems to be some subtle hints of frustration and unhappiness that you probably wouldnt catch onto if you werent looking for it.
I know he's referenced before how florida fans maybe ran out of town some previous coaches (maybe spurrier/ Urban references?) or something along those lines.
Also, I think at sec media days this summer he was talking about how he loved going back home for a vacation ( i assume ) to Montana and maybe even referenced retirement there.