Differences between Chevy and GMC models are largely a matter of noticeably different grilles and subtly different hoods and tailgates. The tailgates are embossed with either GMC or Chevrolet block letters. The front edge of the GMC hoods is contoured differently in order to fit around the top of the unique GMC grilles. You can bolt a Chevy or GMC hood to the opposite-model truck, but the hoods won't fit the wrong grilles. There are a few minor trim variations, but nothing that concerns anyone outside of a concours judge. Since these trucks are so interchangeable, it's easy to use your favorite grille, regardless of the year or make of the cab.
A wild, high-tech liftgate will replace the original "barn doors" on the back of the RB's truck. A lot of metal fabricating skill was required for this change, so we'd advise most people to stick with the doors that came with the truck. Suburbans were available with either side-hinged barn doors or a station wagon-style tailgate and liftgate. The wagon-style Suburban is much harder to find than the one with barn doors. Panel barn doors can be used on Suburbans and vise versa.
Speaking of doors, the '47-50 models had a single-piece side glass. In 1951, vent windows were added for improved airflow. If you like the simpler early doors, switching doors or converting your doors is pretty easy. In 1954, a single-piece windshield replaced the old two-piece unit with its stainless dividing strip.
Two different styles of left rear fenders were available. The spare tire version was recessed to accept a tire. That was a handy place to carry the spare in 1947, but today, plain left rear fenders are the only way to go. Unless the truck is a strict restoration, don't even consider a spare tire fender.
Avoidance IssuesIt's tough to go very far wrong in your choice of a '47-54 Chevy truck project. Stick with the 1/2-ton models unless you're sure you'll never, ever want to sell the truck. The longer bed 3/4-ton and 1-ton pickups barely show up on the popularity radar screen. One good thing about a long-bed pickup is that it isn't difficult to convert to a short bed.
The Serious Hardware rolling chassis is only for short-bed pickups. The cabs and front sheetmetal are the same among the different-tonnage models, so you could put a nice cab from a long-bed model on the new chassis and add a reproduction short bed or try to find a salvageable original bed. The fenders and tailgate can be used from a long bed on any short bed.
Rust is public enemy number one with these trucks. There are readily available patch panels to handle the various lower body rust problems, but it's so much easier to start with the best possible body. The cab's condition is more important than the hood and fenders. The bed's condition is the least critical because there are good reproduction parts available.
Lower cab areas, such as the rear corners, lower cowl, hinge pockets, and the step area inside the door, are places where rust can be the most insidious. The lower hinge pockets are especially difficult to deal with. There are floorboard replacement kits. The areas around the original passenger-side, under-floor battery box are frequently rusted and corroded. The stock battery location can be used, but many builders relocate the battery.
Any rust in the roof could be problematic. We'd pass on a cab with rust around the windows. Even seemingly minor fender damage can be time consuming and/or expensive to restore to acceptable street rod standards. There is frequently a lot of hidden body damage on the fenders. These trucks were used for work, not pleasure, so any damage was usually fixed as quickly and inexpensively as possible. We've seen fenders with a 1/2-inch of body filler covering old dents. Cracked fenders are difficult to repair right, so we'd shop for replacement fenders if any of them are cracked around the wheel opening.