There are a few other things that will show up in AirPlay, but basically, yes. If there are no AirPlay compatible devices in range, the Control Center won't bother to you to show a non-existant option. I'm pretty sure iOS 6 behaved the same way, except the icon was in the Multitasking bar, after swiping it to the right.
A bit more:
Bluetooth speakers and devices will only show up if Bluetooth is on and the device is showing as connected in the Settings > Bluetooth.