Thanks for the responses on this. Man does this issue cause confusion. Before I saw flyingbrick's retraction, I asked the dealer to fix those front signals before we closed the deal on this '03 Ranger I was looking at. My mechanic had said they should blink too. The dealer (a small used car place) looked at it and said they aren't supposed to blink. I called the local Ford dealer and asked and they said they should. I then looked up here and saw flyingbrick's retraction. I then saw a mid-00's explorer with the same front end (roughly) and its corner lights weren't blinking either.
I'm going to take flyingbrick's and gotmudd's word for it and presume they shouldn't blink. That said, I would think it would make sense for them to blink since they would be more visible than the more-inset ones that do blink, but Ford didn't ask me.