As Nate said, that piece is only exceeded by the tub hat sections for rust-out potential. If you don't need it for the PTO or some other loading on the rear cross member like a swing out tire carrier, I would leave it out. It was not a good solution.
I didn't put it in. I don't see what it does besides trapping rust/moisture between the two pieces. Like Bill said, I might be helpful if you are actually going to do work with a PTO.
I think Classic sells it as well, If you are actually going to use the PTO it will help take some load off the rear crossmember for ya. Kind of a pain to install it. It is a tight fit.
Malcom, I'll tell ya, I'm not sure what part you're talking about. I might if my Willys had a rear PTO. If you have a PTO and there is a piece that reinforces the cross member, then by all means you should have it. It may affect spacing and even proper performance.
Walck has piece to reinforce inside of crossmember. Description says it's for PTO equipped. I will reinstall the PTO I got with this Jeep. I don't expect to do a lot of hay baling, but I'd like to stay "correct". Shall I call Carl?