I actually e-mailed him about the mouth before purchase, as I was concerned about that as well, and he said that the mouth is generally closed.
That being said, the Red Haddoni I have has been in the display for two months and has yet to close it's mouth all the way. It never deflates, and is gaining back it's color (was more dark pink when I got it), so I'm not entirely sure what's up with that. BUT it's guts never extrude. Just slightly open at all times.
Good point Todd. I'll keep that in mind with this one, but I'm not sure if a seperate QT will be realistic (my QT is bare bottom, and adding sand would defeat the purpose of a stable tank as it would cycle). Maybe I'll QT it at the local LFS.
Interesting to see what color it ends up.