Yes. I'm sure. For instance, the Listen to Radio activity has only 2 buttons: Preset Up and Preset Down. Watch DVD has TV's "input" button and a couple of DVD player specific buttons (eg. "eject").

It would be nice if under the "devices" on the web site, they had an additional buttons page. Right now there is standard and custom. There should be a "include in all activities" page for exactly this feature. The old "sound" button (659, 550, others) basically did this role quite well-- much better than re-adding a dozen custom buttons to each activity. The Harmony level 2 support person told me that I wouldn't miss the "sound" button at all because of how smart the web page was for magically figuring out what buttons to put on other activities.