I have a Schneider Symmar-S 150mm lens that has something going on inside it. It looks like the coating is coming off the internal elements. Rather than have it repaired, I have an opportunity to purchase an APO-Symmar 150mm that has a broken shutter at a very low price. The shutters are the same size, Copal 0, but if I switch out the elements, will the aperture scale be the same? Will I need to change those as well?