U87s have changed a few times.
There are a few early ones at our studio and a couple of relatively new-ish (early 2000s) ones, and one from in-between. The early ones are moderately different from the early 2000s ones... enough that I might prefer one or the other on something (I tend to like the old ones more often), but not so different that they'd have entirely different applications, for me.
Interesting that you have such good luck with the SM7. I like that microphone, but somewhat rarely on a sung lead vocal. It was just the ticket in one case on a particularly strident female vocalist (who had a theater background, which is a thing I notice often in singers who have theater training). I've also liked it in "live tracking" situations where the singer is playing an instrument at the same time. But in general, I've seldom been as enticed by the SM7 on vocal as many others seem to be.