Which picture are you referring to?One picture is what sets the standard; unless another period photo with as much authority contradicts.
There are 2 1970 Polara convertible pics showing original tops and 5 retouched/enhanced factory pictures of 1969 C bodies just in this thread.
There's also one lone '66 Imperial factory photo that really doesn't have much to do with the discussion because it's.... well... a '66 Imperial and we're talking about '69/70 fuselage cars. I'll even bet that Imperial top was nicer from the factory than the fuselage tops.
While there's nothing that can 100% say that every car came out of the factory with the rear bow wrapping around the side as far as Dave ( @polara71 ) says, it's a safe bet that is correct for these cars. I take him at his word that he has pictures and has seen other cars with original tops.