When putting together a set they test each club against the needed swing weight. If one club needs an adjustment, they epoxy a small weight in the end of the shaft. Does not happen to every club, just ones that might need a slight adjustment to balance the set.

I have four sets of 962 irons that I've reshafted over the last 20+ years. All the sets are 1iron through PW. I've not seen a head that had to be weighted to get the swingweight right.

That has not been the case with the AP2 series or the two sets of TS1's that I have. Reshafting clubs with tip weights can be more difficult. And you need a variety of weights. Few people can tell the difference between one and two swingweight points, but some people can.

I have Vokey wedges going back to the SM5. Many of those clubs also have tip weights.