Which buttons are you inquiring about - on the collective or cyclic? The title says one, your question another.
As others have said, it depends entirely on the model of helicopter. Bells usually work as you said, pull to the first detent for intercom, to the second for radio. But Sikorsky (at least on the S76) does it differently - push up for intercom, down for radio. This is better, but does take some getting used to after 10,000 hours or so in Bells.
Offshore-equipped models will generally have a float inflation switch on the cyclic, and may have a float arming switch on the collective. They can be almost anywhere in reality.
You really have to learn the layout for each model, and think before you start pushing buttons.