Overseer & Nova55,
Do you have the numbers and/or photos of the 1992/3 GMC Hi-rail flatbed trucks, with storage bins down both sides, specifically the first one, which was the oddball of the fleet?
The easiest way to tell this unit from the rest is that the front wheel-wells are 1/3 of the way into the hood, and the cab is not as deep as the rest. Another noticeable difference was that the center cab roof lights on the front were all in one long strip, where as the others were 3 separate lights. Also the front hi-rails were completely under the truck and the bumper was mounted in the factory location.
See the Conrail Encyclopedia photo below for the later version. http://crcyc.railfan.net/mow/vehicles/enolatrucks.jpg
If you want, feel free to contact me off list: rcizik at earthlink dot net.