Duster fuel filler pipe difference between years

There were a LOT of changes in caps. One of the guys here had a great photo layout showing the differences...........

Abody Gas Caps 67-70,70 Cal and 71,72-74,75-76 copy.jpg

If you would just as soon do without the evap stuff, I would modify the neck whileyou have it out, to the 69/ earlier vent