depends on how bad ya want it, how bad he wants to sell, how many others you find around for sale! I've seen decently restored examples advertised for 12-15,000 - NAPCO parts aren't cheap or easy to find if it needs any thing, so I'd say whatever the price range for 2wd pu's is in the area would prolly be about it - 58 was the first year for factory NAPCO - might add collector value
Bill