MJs never got a sunroof from the factory, so it's not something that will have a Jeep part number. best bet is to find a local accessories shop or glass place and see if they have something to fit the hole.
none that I'm aware of for the tank itself (carbed engines didn't have an electric fuel pump) BUT the only MJ that got a carbed engine was the 86 which came in longbed version only. you'll need a shortbed tank.
or it's just a simple Dorman part now.
https://www.amazon.com/Dorman-926-072-Driver-Spring-Bracket/dp/B082P8CX29/ref=asc_df_B082P8CX29/?tag=hyprod-20&linkCode=df0&hvadid=424751278055&hvpos=&hvnetw=g&hvrand=4123504844324291449&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9011095&hvtargid=pla-896674893013&psc=1&tag=&ref=&adgrpid=98636539323&hvpone=&hvptwo=&hvadid=424751278055&hvpos=&hvnetw=g&hvrand=4123504844324291449&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9011095&hvtargid=pla-896674893013
wow. at that point I'd be inclined to hunt down a whole new axle, but I'm not sure how available they are anymore. I'd wager that some company makes aftermarket ones.