I have no dog in this debate but I think the wheel part numbers being thrown around here are causing the confusion.
The 70-71 steelie 15 x 7 is 2944450,
The 1972 steelie 15 x 7 is 3580070.
The 70-71 rallye 15 x 7 is 2944390.
The other later 15 x 7 rallye 3580071, called the Canadian version or over the counter rim has a different size half moon opening.
The 15 x 6.5 rallye for 1972 is part number 3466961.
Both the 450 and 070 steelie 15 x 7 wheels have 4 nub centers