The bars were added in 73 when as mentioned they also pushed the bumpers further out and added the big ugly cushions, this was to meet the new 5mph crash standards. The bars are stand alone pieces that get sandwiched in between the bumper and the bracket, there's not much difference in the weight of any of the bumpers or the brackets themselves.

You could drill some holes in your front brackets, to relocate the bumper closer to the body like the earlier cars. More good info on that here-

https://board.moparts.org/ubbthreads/ubbthreads.php/ubb/showflat/Number/4780596/site_id/1#import