Yup I still have a tube of it from back when I owned an F150. Functionally it did the job -- kind of odd applying a grease that wasn't really "greasy" in texture.
I can't comment on how well it fixed the driveline thump. Since the thump is due to the slack in the spline engagement, it's going to be there regardless of what grease is used. I guess the teflon stuff is supposed to provide some amount of "cushion" to make the thump less noticeable.
I have gone on to use the grease for other applications -- mostly in places where I need lubrication but don't want to introduce anything petroleum based (sewing machines, certain locks, etc.)