Are there "early" and "late" distributor caps?

[35fordtn]

Ford had the tabs for the outer cap alignment for a reason. In most all cases ford did things for a reason.
Without the outer tab for the outer cap it allows the outer cap to rotate. If the outer cap is not aligned properly, then the cap bails do not properly set between the "humps" of the outer cap and come loose..... Don't ask me how I know as it follows with a very embarrassing story