The boat comes with the Magnum Wings. . .
Correction, those are SX wings. And the rudders are on backwards, switch sides.
The boat needs a bunch of work, but if you're willing to do it then it could turn out very nicely. Polish, lube, scrub it. Most of the replacement parts can still be had, such as sails, shrouds, anchor pins, sheets, halyards, main and jib blocks, port covers. As already mentioned, if the hulls, cross bars, mast, and rudder assembly, and dagger boards are in good condition then it's just a matter of how much money and time you want to spend fixing her up. Just ballparking, I'd say the cost of the parts I'd want to replace would be near the purchase price, but that's me, and I'm a bit picky in keeping my boats in safe and good working condition (I finally fixed my rudders, Cork Guy!!)
There's also the question of your local market availability for these boats and how badly you want it. I think your offer of $1600 is fair considering all the work and parts that it needs. And if it comes with the beach wheels then check the condition of the tires.