Law says that "in the middle war years, a large number of K.98k's were issued without the rear sight leaf pin; however, use of this part was later reinstated following numerous reports of lost rear sights." In that period, sight leaves without the hole might have been used.

It seems unlikely that sight leaves without the pin would have just been "lost". I suspect that pin was intended to eliminate the "fiddle factor", soldiers fooling around with their rifles getting the leaf off then not being able to get it back on.

Jim