Interestingly enough, while I can't claim the pics are of untouched originals, the first is a 67 and has the cap like your 67 - but all the others are 68s and have the other cap as you've mentioned. (the last one is Reggie Jackson's
![Smilie](http://67-72chevytrucks.com/vboard/images/smilies/smile.gif)
) Anyway, at least based on circumstantial evidence, it does appear that the oil fill cap changed between 67 and 68.