Buddy has a '14 or '15 Dakota (I'm surprised how heavy it is) it has a long tail light across the back, water got into it, a segment of LED's don't work, but otherwise no other issues.
In the case of this ford, would drain holes have helped? He replaced both lenses? Why?
Why do you need a complete new lens when the short connector assembly inside the lens is the problem? Take the connector out, let it sit in vinegar for a few days, it's fixed. Now this mechanic has a perfect pair of lenses on hand to use to repair a non-radar truck. If it were me, I'd remove the GD radar thing in the lens and then (if possible) de-activate the dash warning message and be done with it.
I had a bus problem on my '01 Ram about 10 years ago (it has only a single data bus, 2 wires) I unwrapped the big wire harness in the engine compartment, traced the problem to the big square connector at the fuse box, everything looked perfectly clean, moved some pins around and problem gone. Hasn't come back.
If I can help it, my '01 Ram (with 45k miles and no rust) and my 4 300m's will last me another 30 years of daily driving (assuming they'll still be selling gasoline all that time).