The old thread has this: Buy quantity 4 of Ford part # W705903 S300
But, when I went to my dealership here (Kansas) that part number didnt translate, so I ended up having to go through a few different diagrams with the parts manager to find what I want. I also think you can get them for an F-250 and might work.
As I recall 4 were around $12 for my truck. Helped for a bit, but my doors are back to rattling again..grrrr