Fuel pump assemblies are universal - they will fit both tanks.
If yo look at the fuel pump assembly it has a part that extends out.
It will extend all the way to the bottom of either tank 26 or 35 gal. No problem.
If you have a full tank you dont have to take off the whole bed but only tilt it so you can get to the fuel pump assembly.
For me this was easier than dropping a whole tank.
6 bolts holding the bed onto the frame and 3 screws around the gas cap.
Tilt the bed and prop it up with something - make sure its safe.
Unscrew the retaining ring, unplug 1 connector and 2 hoses.
Pull the pump straight up.
Each pump assembly comes with new float and fuel level sensor.

 

Tilting the bed and making sure it's safe is where the hazard lies. Working with gas is dangerous enough, I personally won't add any other risk. JMO

Oh and btw, the fuel pump might be universal for that year truck, but it is NOT for later models, like my 98 for instance. Just sayin'