fuel tank swap filler neck question

[Bunky67]

I have a 77 CJ5 and rear tank and I want to put in a 78 tank.
I have a couple of questions

Is the filler neck that attaches to the hoses different or just the mount on the jeep?

Does the 78 tank have the hook ups for the roll over valve and charcoal canister?

 

[Posi]

The only difference would be where it mounts the body the 77 is round 78 is not all else is the same including RO valve.