The "quarter light" (just to add another term) windows were dropped starting with the '74 model year, so... the car is probably an early '73, or a late '72. I used to have a similar car... don't remember exactly, but as I recall, it had the early bumpers and grille, but had the late tail lights and interior.

I always had assumed it had been in a wreck, and someone did some odd swapping or front and rear body panels, but apparently it was not the only one...

Do tell what the actual build date is as Ken mentioned... perhaps its a Canadian built car and they did things a little skewed...?

-Matt