IF it's not avail. from Ford, MANY shapes & sizes are avail. at an auto parts store like NAPA.
Take a sample with you, or draw a diagram of what it would look like from the side (as in a cross section view) plus a measurement of the width & height.
Looking at their catalog of weatherstrip in the store, you'll see a shape picture, dimensions, and often common uses listed.
Same basic style & size will work, even if not identical.
They'll sell you official weatherstrip cement as well, since except for odd places like the extra piece at the bottom of our doors MOST is glued on.