Myself and Beepbeep talked with Tom at M+H a few years ago on this very subject.
There were at least 2 different venders suppling coils to Mopar back in the day.

Essix coils were typically green lettered and will have the 'made in usa ' printed on . Then there was the yellow lettered coil, that will have the 'made in usa ' cast into the top plastic hat of the coil near the tower (sorry,I can't remember who the vender was of the top of my head)
Yellow lettered coils 'as a general rule' were approx 1965 and earlier, ALTHOUGH some newer cars up until at least 1970 have been found with yellow lettered coils.

Essix also used at least 3 or 4 different can to casing crimp styles.

So variations in can size is a possibility.
So, it may very well be possibile to have a differnet can on various models thru the years.

Also, Tom has an internal enginering sheet to specify the change in lettering style on the can. approx Nov 1967 the CH412 was to be deleted from the case lettering, all coils prior to this date should have it, and if you allow approx 30-60 days to enter production approx anything after Jan 1968 will not have it.

ps- I have several used originals on hand as well as the repops, I'll do a comparison on can dimensions this weekend to compare and report back.
I also have a few NOS coils on hand but they're all 1972 date thus have the square box/mopar flag on them so I don't know if the can design will be relevant

WITH the CH412

Without