It is late 1972-Crush em if you got em.

[njsteve]

The door beams were already in place from 1970. I thought it was the new for 1973, 5 mph bumper requirements as well as upgraded emissions systems? The 73 Firebirds have about 50 lbs more steel bracketry inside the nose. Also, the urethane nose itself is different though it appears very similar to the 70-72 noses to a casual observer. The grills are only half the depth of the 70 to 72 grills to allow for all that extra reinforcement. That is also why the hood release was relocated via a cable to the valance opening.