It's got one. The IVR is built into the Fuel gauge. That's how my 64 Valiant is, anyway. Yes, the connector is keyed and there is no retaining screw. Just grab the connector and gently "rock" it back and forth while gently pulling on it. They can be stubborn. Sometimes unfortunately, a pin or two will break off of the printed circuit board. If that happens, clean both up and carefully solder them back on. The cluster grounds through the mounting screws, but it doesn't hurt to run a dedicated ground wire too.