As that was Kawasaki's version of the Yamaha DT350 I would assume it should be worth something. It all really depends on your market. Here in Colorado a good DT1 (250, can't find anything on the 350's anymore) is still worth about a grand. Can you still get parts for them? That might make a difference on price.
There is a 73 on Flea-Bay right now asking $1499 but no bids. :roll: I think he is a little proud of it.
I would honestly thing you should be able to get somewhere between $900 to $1200 for it.
Best of Luck.
Marc