Here are some pictures. This would be the "early version", and molded in light gray plastic. It was in the back seat of a 68 Montego MX with AC, which should get a heat shield based on the MPC. However, a 1968 model year car and a "late 1966 or early 1967" date range don't add up.
There are about 20 1967 model year Mustangs and Cougars here, but none with A/C, which would be what to expect up here in the north. There is one S code 67 Mustang. Other than A/C, I don't recall what would drive this being installed on a Mustang or Cougar.