My knowledge of optical physics is sadly limited, but perhaps someone here can h elp me.

I have an old Apo-Ronar with some fairly substantial damage to the coating on th e front element. The damage is central, and covers about 50% of the area. The gl ass otherwise seems perfect. Since it is a symmetrical design I could simply swa p the front and rear groups around, to make the pristine rear element into the f ront element.

My question is, would there be any real point? I can't quite decide whether I th ink a damaged front coating matters more than a damaged rear coating, or whether there would be no discernible difference. If there is even a small benefit I ma y as well take advantage of it.