What have I got?

67s had round radio knobs and 68s had the thumbwheels. 68s have a longer lower dash pad that makes a great shelf for putting stuff on, 67s don't have much of a lower dash pad. You have to take out the windshield to swap out the dash.

You have a very solid car there and I wouldn't sweat it. For me, I like the 67 tail lights anyways cause they have more surface area for the brake/taillight.