jett, it's been a long time since I used my 6x7, but I bought it with the standard prism in the early 1970s, and got the metered prism not long afterwards. I didn't notice any change at all in the image I saw in the viewfinder -- just a big improvement in ease of use. At the time, unmetered prisms were available very cheaply, since everyone was exchanging theirs for the metered variety.
In the period during which I used the camera, from 1973 to about 1995, I had two or three different 105mm lenses, the last purchased in about 1990. They looked a little different but, to my eyes, had exactly the same optical performance. I guess that, optically speaking, only the coating changed. Nettar