Is this something found on other cars BESIDES just the O.P. 's application.
That is commonly known as "application", also known as "where used", as on other cars of the Ford lines. How you "apply" paint is another use for the word "application" (isn't English fun).
Now, to an "application" technique. I bead blasted almost all the pulleys used on my Mustangs, then paint them. Paint in the "groves" can cause belt slippage. Ford had a 3/8 to 1/2 inch wide rubber ring of appropriate pulley diameter that went in the grove as a painting mask. Now, where do you find a rubber ring on short notice? I used 1/2 inch wide masking tape to mack the grove, several wraps around, stuffing, twisting and covering out to about 1/8 inch of the edge of the ring, then painted. A couple of minutes of the car's engine running "softened" the painted edge, just like an original pulley would get.
Jim