Why yes, the 96-00 civic (P.N. 76430-S01-A01ZA) interior mirrors do, in fact, fit in place of the discontinued 88-91 Civic/CRX mirrors.

The 1990 Civic Hatch I drive has a mirror which I can't tighten up, and it moves downward over every bump. I have a spare I got from another '90 hatch and it is the same way. I did have one I took out of a 1991 CRX parts car, and it was made differently. It was adjustable, I think. Anyway, it was nice and tight, and I was gonna put it in my Civic, but I ended up putting it in some girl's Civic instead for some reason. <3

So I don't know if there was a plant difference, or CRX/Civic difference, or a change in 1991, but that was a good mirror. If, however, you have a shitty mirror, like I did, the 96-00 Civic mirror, Part Number 76430-S01-A01ZA, is still available, and does fit.

So, I put a 1991 CRX mirror into a 1990 Civic Hatch, then I just temporarily put that shitty mirror in my 1998 Civic hatch, and put the one from the 1998 into my 1990. All fit flawlessly.

I'm going to buy a new rear view mirror, Part Number 76430-S01-A01ZA, for my old 1990 Civic and put the one for the 1998 back in place.

I might buy two because surely they'll be discontinued as soon as I fall into another CRX/Hatch with a shitty mirror.