The value will not diminish as your "VIN", or serial number doesn't indicate wether it was a 3 or 5 window(yours is a 3, the 5 is with the cab corner windows.) It was just an option from the dealer, and unless you have the original build sheet (did they even make those for these old things???) no one will know otherwise.
I think this is exactly what you are trying to do, judge for yourself if its out of your comfort zone.
I could be mistaking but i think the creator of the video is a member on the forums here as well. maybe search and shoot him a PM.
