The Correct answer is yes...all late build 71 A/B/E bodys use the 72 slotted bumpers.Early bumpers used up to June ,slotted after.It's in the Master Parts Catalog people.
But whats up with Challenger fronts? 2962348 ,chrome used up to Feb 71 3595062, chrome from Feb 71 to June 71 3595032, chrome after June 71 (SLOTTED)