The color shades may vary significantly depending on how your monitor's brightness and contrast controls are set. Of course, metalflake paints look drastically different when you look at them in different lighting conditions.
Cameo
Ivory code "11" "C"
Porcelain
Blue code "24" "D"
Admiralty
Blue code "29" "E"
Regatta
Blue code "26" "F"
Desert
Sand code "56" "H"
Golden
Olive code "46" "J"
Verdant
Green code "42" "K"
Slate
Green code "44" "L"
Brewster
Green code "48" "M"
Florentine
Red code "74" "S"
is probably the incorrect number as listed in other sources.
Here is displayed "75"
Ascot
Silver code "64" "V"
Valencia
Gold code "60" "Y"
Burma
Brown code "88" "Z"
is probably the incorrect number as listed in other sources.
Here is displayed "68"
The vinyl colors:
I have not confirmed the exact GTO names, but here are the general
1973 vinyl colors:
Black
White
Medium
Green
Medium
Blue
Light
Neutral
Chamois
Maroon
Thanks to Roger Lachele of Texas for loaning me his 1973 paint chips to scan.