I'm confused...
You mean, you never saw your hood turn signals--because they were not positioned properly?
As for the '68 hood. The Louvered hood (with turn signals) was an option for '67. it was "supposed to be" a standard item for '68, and was so on all the '68 Mustangs built before Jan 1968. The Fed mandated safety features, specifically the shoulder harnesses, nixed the louvered hood as a std. item, and it went back to being an option.
The turn signals in the hood is a carryover from the Thunderbird of that era.
The louvered hood was part of the GT/CS package--so all of you should have one.
An interesting side note--I once thought how cool it would be to make a small sequential flasher in the hood signal lights; divide the housing into three parts, and put in three lights (LEDs), to blink "1-2-3", left or right.
Also--if you had the 428CJ hood scoop, the flashers were moved to the rear of the scoop, since you couldn't see the right side one if it was in the hood, blocked by that big air recepticle in the way!
Paul N.