if he reckons that it needs no money spent on it well that is only his opinon, its different when You buy it of course as everyones standards are different (you may want new tyres, chain & spockets, Bars, etc)
$3k is not shit loads for a big bore 2 stroke from this era if its as good as what he says. i would suggest go right over it and check as much as you can out. even if you found one that was rough but resonable it can cost you way more in $ and time once you start to restore them. so if its a real good one i would pay that. if frame is done well (i can't tell from the pics) it should be ok, mine was too far gone in a few area's to warrant repair and i saw the 86' frame and got it at a better price than i could of repaired mine for. of course haggle him down a bit if you can.
just noticed that something (other than the color) is not right with the seat ?