Look at the dash where the half round chrome trim goes over the column, I s it metal or plastic?
Look at the dash colored piece under the column, is it metal or plastic? METAL

Plastic is 67, metal is 66 and they will not interchange. Metal dash frame is different. METAL

Look at steering column, is it painted a satin color or full gloss? Look at column under dash near brake pedal, does it have a part of the tube 6" long that is a mesh? By hat is a collapsing 67 column. STRAIGHT COLUMN

Is steering wheel colored like the interior? Does it have 2 spokes or 3? TWO

Does the console have the end piece bolt on? Look inside the console box and you will see the fast ers inside there on the rear end. You can see the seam on the outside. YES BOLT ON

66 and 67 front fenders are different where headlight buckets mount, weld on in 66, bolt on in 67.

The 66 and 67 heater boxes are different in the way the metal brackets are attached also, need to go in garage and look at that again.

Generally August 1st started the next model year car production.