Pristine engine bay in '66 Chevy C10 with 327 & factory A/C

[HOTFUN]

Yelmer. Your guess is as good as mine on the head markings. I looked at mine today and it just has a small yellow mark on the front of the head. Appears to be like a "8" but can not really make much out of any of it. I will have the motor out in the next week so I can view the back of the head.
My engine code is F0707YR and is the original 327 4 barrel with PG for now. Also went and tore into the dash and the AC center vent cutout appears to have been factory modified before the dash was painted and the engine side firewall markings, though very faint , appear to show A/C letters just to the right of the paint code in the center. So getting back to the factory AC pullies and paint color on mine. The lower alternator bracket has engine green paint paint. Water pump pullies are steel and are two seperate pullies put together and both painted satin black and a 5 blade fan with a small spacer (no clutch fan). The lower factory single pulley(fan/alt belt) and harmonic balancer appears to been green and a bolt on cast iron 2 pulley(AC center- PS outer) was a redish brown color paint and has a GM casting # on it. The factory PS pump is satin black reservoir with a silver or cad plated cap and it's single pulley is natural steel with no paint. So question being using the clutch fan style WP pulley, what colors were the upper and lower cast pullies originally? And what were the reasons they either used a fan clutch or not?