[Yukon Jack]

If the original has no pin holes and appears to be sound, I'd just use it. If it has any issues, I'd use the repop.

My solution with the repop is highlighted in the above thread - I cut the old one off, used a piece of fuel hose to connect the used neck to the stub on the repop tank and it worked great. I had originally cut my original neck off and soldered onto the repop, but still had fitment issues so ended up cutting it off again and using a the hose to add the old to the new.