Looking at distributor caps for my 1973 440 and trying to determine which style cap actually was used when it was built? I'm seeing caps with both a thicker & thinner perimeter outer walls. Both use the same 2444507 part#. I have electronic ignition which maybe is when they made the change, or it could just be when they determined less material is more profit. I realize each would work but I'm looking more towards what was original and if there was a reason why they were changed. Thoughts??