According to the Chevrolet Truck Data Book, the 3105's "curb weight" (empty of cargo) is 3,555 lbs -- which would correlate to your "unladen weight." As for Max gross weight, as Otto says, that should be on the data plate. I doubt you will find a max GCVW listed anywhere for that truck as they weren't really intended or designed for pulling trailers ... originally, anyway. But maybe there is such a figure in the source that Joe mentions.
Seems strange that they would even need that info for an antique vehicle. A lot of states put "0" down for GVW and GCVW which is why you don't usually need a CDL to drive antique-registered Class 8 trucks, for example.
Hmmmm.
