I have that amp docked on a 12T and I have the 210T as a second cab. It comes as a combo either way. NICE combination. Used I'd say $600 is quite good, because retail is more than $1200. Dickering is always worthwhile, so why not give it a try?
You won't be disappointed - it's a really good combo.
"The best way to tell a lie is to tell the right amount of the truth, and then shut up." Robert A. Heinlein