The 2010 came with bar end shifters (9-speed).  The seat damage means either it was well ridden or the user was a heavyweight.  A new seat costs a good bit, but you can also find out from Mike at Easy Street if the new padded seatmesh will work on the 700.  Still, if it is otherwise in good condition, $1600 isn't bad, but the seat gives you some haggling room.
 
If you are thinking of racing, you should probably look for the newer model, which is potentially faster, with the 20" wheels and more streamlined position.  For just going long, I like my 2010 model better, but a seat pad helps.
 
The original Dura-Ace right shifter may have broken (it's what they do).  When mine went, I took advantage by converting to 10-speed, with SRAM bar-end and derailleur.  No crank change is necessary.  I wouldn't think twist shift was necessary or desirable on the 700.  I bought my 700 in 2010 and have put around 15,000 miles on it.  It's still solid.