Curt,
Can't speak to the type of shank per years, but tappering them without filling in holes after ball studs are removed was not necessary in the set I did.
On a related note I pressed out the other 3 studs today and found a slight chamfer on the backside (peened end) of the pitman arm ball stud. This is opposite of the other 3 removed from the steering arms where the chamfer was on the top (ball side). Either was a non-issue.
http://www.flickr.com/photos/dodsonbrett/sets/72157627652317197/Cavebull
