August 1st was a Tuesday in 1967. 1968 was a leap year, so instead of the following years date being one day off as usual, its 2 days off. (usually if august 1st one year was a tuesday, the following year it would be a Wednesday). Calendar week of August 1st 1967 could be either an 07E build week (if one exists) or 08A depending on how Fisher dated the tags since the calendar month changed after the start of the work week.