Most early SPD '71 B-bodies have been documented as having '70 style covers, so I would "guess" E-bodies would follow the same rule of thumb.
Not surprised.
I'm in the process of putting together my 71 Challenger R/T 440+6 after being apart for 19 years. I've had 5 other 71 cars in the shop to reference off of and there seems to be no shortage of mid year changes.
