Does treble response beyond my hearing matter?

Yes, first you buy an amplifier with super-wide bandwidth and then buy Transparent cables to limit the bandwidth.
IMO, the way you are approaching this is putting you straight on the road to audio hell. Everyone does the same thing - they buy products that are "revealing", "detailed", "heard things I never heard before", supertweeters your dog can hear, etc. Then they come on to A'gon and bitch how their systems are bright and harsh.

Just listen to some speakers and buy what sounds good. Don't worry about the specs. All of the speakers you could reasonably buy go out as high as you need them to go. If you can't trust your own ears, then find someone whose ears you do trust and let him pick the speakers for you.

On the grand scale of things, no.

Mapman, why? Even if I can't hear above a certain frequency, in the range that I do hear, wouldn't having a higher treble response add to "air" or sparkle? I think that is what Arnettpartnetrs was alluding to, or at least in part.

I'll certainly listen to speakers, but some that I am considering are ID. Some have great shipping/return policies while other are just fair so I'm looking for ways to reasonably narrow the field.

I wish I could find the link, but I was reading something the other day on hi resolution audio and it talked about why Redbook CD is more than adequate to exceed the human capacity for hearing. The interesting thing was that the high res media could include things behind the range of human hearing but in some systems it could actually cause distortion in the audible range. It seems that higher could do nothing if you can't hear it, but could add distortion within the audible range under some circumstances.

Don't worry about what you can't hear, just judge based on what you can.

Fin,

If the specs look good up to the limit of your hearing, you are probably in pretty good shape, no matter what might be measured beyond.

When I was young, I could hear test tones up to 20khz. Now, at 54, only up to about 12-14 or so. That's typical of how our ears age.

It can be a good thing though. By design, not much music occurs in the upper ranges of human hearing, but a lot of noise and distortions can. So not being able to hear up there can be a blessing. I find most music a lot less fatiguing these days than I did in my youth.