1968 Z28 Alternator Fan Question

[169INDY]

I was at a car show recently and a 69'er fella brought up the topic of some Z's use Hook style Fan with regard (application) to my 68Z.
I stood there with a silly (confused) & grin w/o questioning in my mind why (?)
my 68Z  1100814 37 amp date coded 7H10 Alt has a 1967 style fan on it.
It really looks like the 1967 Fan shown in 67-68 302 facts book (rev 4) page # 14, it (Alt) does have a 3.200inch deep groove pulley.

OK, Can this be a situation like; 2 codes used in 68 for the Dizzy, early car Black Ashtrays, Non disc brake pedal medallion pads, & all these little differences we encounter along the way?

This may have been discuss before, I search a bit before asking.

Opinions?

JIM