I have a p67 with non metered prism. There is what looks like some de silvering going on, right smack in the center where it bugs me. I was looking at KEH for a replacement, and there are a bunch of different metered models. I would just as soon get a meter, but have no idea what the differences in the models are. Can someone steer me in the right direction? Also, is it possible to get diopters for the finders?