"Trim Grade/Class" VIN decoding?

Is it a Formula S?
No, which is why I'm a little curious as to why it's an H. The VIN is BH23F8B121258, which from what I've researched means:
B - Barracuda
H - High trim grade
23 - 2-door Hardtop (Notchback)
F - 318-2bbl.
8 - 1968 Model year
B - Hamtramck, MI plant
121258 - Sequence #

The car is a 318/904 car originally, with heavy duty front and rear drum brakes. Column shift, no center console, no rear armrests, I think the car may have originally had a map light switch (there's a hole in the dash in the appropriate spot), but it doesn't have anything fancy like a rear defogger or anything. The interior color is red with white bucket seats, lap belt, and a day/night mirror.