I.B. Color Code (Interior Body)

The 4th box from the left on the top line contains the code for the interior body paint. As near as I can tell at this point, all interior trim combinations could be handled with six build sheet interior paint color codes, described below as Group 1. Items in blue (below) indicate common standard and deluxe trim items that were painted Group 1 colors.

The Ford assembly line couldn't have painted the complete interior from the build sheet codes represented here, as they only provide for Group 1 colors. They would have had to see what Trim code was indicated in order to paint the associated Group 2 accent colors.

11/13/10
I had been using a table found in Larry Dobbs' book How To Restore Your Mustang as the basis for my initial research. The book has a table for 65 and 66 Mustangs with trim codes and color info. Mr. Dobbs uses the same codes for both years. I found out yesterday that this may be incorrect. While some codes were the same, some were different. The Aqua/ Turquoise and Red changed from one year to the next. There may have been other changes. I'm continuing to research the Red color code, as there's some opinion that 1967 Dark Red #71566 was used in 1966. My table below has been updated with the current information.   

I.B. Color Code (Interior Body Color)

Group 1 Colors
D	Parchment			Ditzler #22669	6		Black	Ditzler # 9295
2	Light Blue			Ditzler # 13004	7		Light Turquoise	Ditzler # 13025
5	Red			Ditzler # 71541	1		White	Ditzler # 8612
Group 2 Accent Colors
	Medium Palomino			Ditzler # 22519			Red	Ditzler # 71541
	Medium Blue			Ditzler # 12989			Dark Red	Ditzler # 71566
	Medium Ivy Gold			Ditzler # 22517			Medium Emberglo	Ditzler # 60485
	Medium Aqua			Ditzler # 12993			Dark Emberglo	Ditzler # 50721
	Black			Ditzler # 9295			Burgundy	Ditzler # 50724
Notes:
Group 1		Standard Interior	Instrument panel, steering column, steering wheel, kick panels, windshield post, sun visors, metal door surfaces, quarter trim panels, 2+2 overhead molding, console, rally pac (rally pac could also be black), door panels & arm rest pads on parchment trims C2-C9 & D2-D9
		Deluxe Interior	Instrument panel, steering column, kick panels, door panels & arm rest pads, console, rally pac (rally pac could also be black)
		Factory Trim Code				Interior Paint Color
		62, 67, 68				White
		27				Light Turquoise
		22, 32				Light Blue
		25, 35, 65				Red
		64, C2, C3, C4, C6, C7, C8, C9, D2, D3, D4, D6, D7, D8, D9, F2, F3, F4, F6, F7, F8, F9				Parchment
		26, 36, 66				Black
Group 2		Standard Interior	Dash pad, radio speaker grille, lower windshield molding, carpet, seat belts (seat belts could also be black), door panels & arm rest pads except parchment trims C2-C9 & D2-D9 (see Group 1)
		Deluxe Interior	Dash pad, radio speaker grille, lower windshield molding, carpet, seat belts (seat belts could also be black), windshield post, sun visors, metal door surfaces, quarter trim panels, 2+2 side vent panels, 2+2 overhead moldings
		Factory Trim Code				Interior Paint Color
		22, 32, 62, C2, D2, F2				Medium Blue
		68, C8, D8, F8				Medium Ivy Gold
		C9, D9, F9				Medium Palomino
		27, 67, C7, D7, F7				Medium Aqua
		64, C4, D4, F4				Medium Emberglo & Dark Emberglo
		C3, D3, F3				Burgundy
		26, 36, 66, C6, D6, F6				Black
		25, 35, 65				Red & Dark Red