Finally took the time to replace the rear window runs in the tailgate. Thanks to @thedeuce01
for pointing me to what I needed on Dennis Carpenter, they were a perfect fit. As he mentioned, it comes in one piece, so you have to cut it in half. I did that, and in my case each piece was almost 1/2" too long. See the pieces I cut off in the middle of the pic.
They can be installed without taking the window out. I let the tailgate down, removed the cover, ran the window all the way out and supported it on a sawhorse. The hardest part was getting the old ones out as they had hardened and had to be broken out in many pieces as you can see below.
The window is still slightly in the track, so I started at the top, pushed the new run in for just an inch or two, then pushed it up until it was even with the top of the track. I had to lift up on the glass (from the outside just a bit for the run to move into the right position.
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