I am pretty sure that the 66 and 67 model years were virtually identical body wise. The bumpers should be interchangeable.
I'm no expert, but from what I've observed, '67 front bumpers are much pointier than '66 front bumpers. You could make the '67 fit... but it wouldn't match the lines of your hood and grill. Probably look pretty bad. ~Mike '66 Skylark 340-4