I bought a brand new 1990 W250 4X4 LE, which is one step up on the trim level. Every available option you could get with the truck I factory ordered except for 2 tone paint, and I wanted a 4 speed not the automatic. Has A/C, windows, locks, auto front hubs, Dana 60 rear with floating axles, cloth interior, all the chrome trim etc.
INCLUDING the 8% tax in Connecticut the truck was $16,100 OUT THE DOOR! Based upon what you told us about your grandfathers truck, I think $10,000 is VERY close to what he paid for it brand new if he is the original owner.
Having said all that, when I bought my truck all my buddies and family members told me I bought the biggest POS truck on the market. Well guess what....all their cars/trucks (GM & Fords and even a few imports) are LONG gone, and the Mighty Dodge is still here, still looking like new, and has over 200,000 trouble free miles on it.
If you can get that truck for a reasonable cost, DO IT. It will run like a bear, pull a mountain down and outlast you & I together. I know mine will.
Good Luck!
George
