11 total screws to remove the dash pad: one on each end of each defrost vent, two above the glove box, and two behind the instrument panel trim, which is itself held on by three screws that go up into the dash pad. As was said, there are two 3.5" speaker mounts at the corners, and 1 5x7" mount in the center (used for the amp in the premium systems; was for a single speaker in old AM-only mono radios).
You might call Matt at
Fox Mustang Restoration about a reproduction dash pad; I saw a thread at
FourEyedPride.com a while back where he was working on getting a better quality reproduction made. Not sure if they're available yet or not.