I'm willing to bet that this was originally a CA truck, but it's not there anymore. This is an E4ME Quadrajet, which is what came in 1981 Corvettes and GM B & G Body cars from about 1980-1990. I know that 49 state square bodies never got this. California, I'm not 100%, but I feel like they did. I see that there's a CTS in your water neck, which is where it is in my '86 Caprice that has the same carb so that's another clue for me. If you still have the wiring harness mostly in tact under the hood and the ECM and harness in the cab, then absolutely rebuild it. You can get the pigtails and stuff to make the sensors work, and it'll run pretty damn good once you get everything hooked up. However, it running good is contingent on all those sensors and your ECM working. It'll run like ****, otherwise. I don't recommend you rebuilding it yourself because it's more complex than say a run of the mill Quadrajet. It's got a Mixture Control Solenoid that has to be adjusted to a specific dwell, and the carb also has a TPS sensor in it. I know that sounds really complex, and it is more so than a regular Q-Jet, but I sent mine in the mail to be rebuilt at Mountain Man Carburetor in Hackett, AR. They rebuilt it, put a throttle shaft bushing in it, cleaned it up, and set everything to spec so, minus the idle mixture, it was bolt on and go. I get about 20 MPG on the highway with it, and minus the bolts getting loose when it got cold, the carb hasn't given me a problem. Before doing anything, though, make sure you have a harness coming out of a computer or just the harness if the computer's not there. I would guess mostly everything's there because people are generally too lazy to pull it all out when they ditch the Computer Command Control (CCC) system. Mine is located inside the passenger side kick panel, but I don't know if they would have put it there, behind the glove box, or even somewhere else in your square. Here's my E4ME before rebuild. It had 246,000 miles without a rebuild and was running not great but okay.
