Are there different lock tones for different types of missiles, e.g. air-to-ground (AGM) or anti-ship (AShM)? If so, what information do the tones give the pilot? Are they a way for the pilot to know which type of missile is selected?
Lock tones are normally used for (surface/air)-to-air infrared homing missiles. Air-to-surface missiles don't "growl".
The tone is used to indicate missile readiness and quality of lock, not the type. Phantom pilots in Vietnam used to cycle between all available Sidewinders to check which seeker had the best tone then put the worst one to be last in the firing order (source: "Sierra Hotel : flying Air Force fighters in the decade after Vietnam" book, page 12)
At first there was a volt-meter in the cockpit to do that, but during development testing they figured out looking inside the cockpit in a dogfight to check if the missile is ready to fire wasn't a good idea, hence the tone frequency was introduced (source: Fox Two).