Your truck probably came from the factory with this carb, according to the number/model. It would be jetted correctly for your engine. If the truck runs good other than the choke issue I would fix the choke; being the least expensive option.

The po installed some form of manual choke. You should be able to remove it with the three screws. Then replace it with a 12v choke cap, adj for proper operation and be good to go.

They also put the hot air coil in upside down. Lower left tube affair. Unbolt and invert.

I would also check the egr canister to make sure you don't have a vacuum leak. Light gray hose.

I typed a much more detailed response but closed the window and lost it....

Hopefully others will add their input.