Under Keyboard Settings -> Keyboard Model, I don't seen any choices for the standard 87 or 88 key models. I haven't encountered any problems, but I'm using an 87 key US layout and assuming that KDE would treat it the same as a generic 104. Would someone be so kind as to set me straight or enlighten me as to best practice in this regard?

I would assume you are correct in your use of the 104 key layout - from what I can tell no documentation exists for an 87 key layout.
(Please note that the keyboard layout itself is handled by a system known as "Xkb" which KDE is providing a convenient interface for).

Thanks for your time bcooksley. It seems a little odd that there are none of the "tenkeyless" keyboards in the list since they're getting quite popular. I would have thought that at least some IBM version would have been mentioned since those go back to 1981. However, since I still haven't seen any problems, I suspect the choice of keyboard in that list is generally not critical. Thanks for the pointer to Xkb. That's worth learning about.

Not a problem - if this resolves the issue could you please mark the issue as solved?