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)
I have always found the three chrome bumpers on the front of a 1971 Challenger just a weird Chrysler thing in the parts book and on the cars. I assumed that the 1970 bumper was also 2962348 same as the first 1971 Chrome Bumper. Lent out my 1970 parts book so I can not check to see the number in that book is 2962348 for 1970 front Chrome Challenger Bumper.
Challenger Rear Bumpers
2962350, All 1970 rear Challenger Bumpers.
3464073, up to June 1971 rear Challenger Bumpers.
3595038, after June 1971 rear Challenger Bumpers.
My June Built Challenger has both the front and rear slotted bumpers. My September Built Challenger does have the normal looking bumpers but I would have to compare to Feb. to June built front Challenger to see what the difference is between the early Challenger bumper and the middle Challenger front bumper.