73 VS 74 Duster Front Bumper Differences.

A '74 with a shock bumper in the front?

Never even heard of one. Every '74 Ive seen has had the standard front bumper and a shock mounted rear bumper. Not saying it didn't happen, I haven't seen them all and Ma Mopar did some weird stuff, but...

Are you sure it's factory? One thing I have noticed about all the '74's I've seen is that they had the captured mounts for both the standard brackets and shock mount brackets. Meaning, a shock mount bumper could be installed with no changes to the car other than the bumper and plastic filler piece, the frame is set up for either type.