I'd buy it, for $1,500. The dealer is never going to sell it at that price, wave $1,500 cash in front of them and they will probably bite.
At that mileage it could be in decent shape. The trans and front end might be pretty recent. The engine will go a long time, the timing chain was probably done. I'd just pop the valve cover take a look at everything and measure stretch.
I think the 602/3/6 series has a stronger bottom end than the old 616/617's. But I'll get flammed for that. All I know is damn near every 616/617 I see has a ton of blow by, and I have yet to see a 602/3/6 that does.