will 70-72 bumpers bolt to a 73?

I've had three '74s with non shock absorber bumpers and one that had the shock bumpers, I believe the shock style were optional in '73 and manditory somewhere around mid '74. My '74 swinger built in 4/74 has holes for both style bumpers but still has non shock bumpers on it, it did have those big rubber bumper guards on it and the heavy steel reinforcement behind it which made it a "5mph" bumper.