certainly that can happen, however, in my experience, that's not usually the case. I've been around plenty of high mileage mustangs, mine included, and have never seen that and classified that as a normal noise.
often, (more common than pivot ball or fork wear) the noise is from a misadjustment of the clutch. If the clutch is adjusted too loosely, then the t/o bearing will not have the right amount of preload on it. The clutch and t/o bearing in the mustangs are designed to have a constant preload on it, meaning the t/o bearing must constantly have pressure against the pressure plate. if the adjustment is too loose, then the t/o bearing will essentially be there, half spinning, have flopping against the pp, causing that scraping/squeaking noise that is common. Not always, but more often than not, a quick adjustment and tightening of the clutch cable will cure this. Just know HOW to adjust a clutch when you do this, and when is too tight, and when it is not.