Below, I have included pictures of underside of my known original, date stamp supporting, SJ final assembly date 11/02/66 example. Very IMPORTANT NOTE: This fender was originally Ivy Gold, so the darker underside of fender coloring best represents the actual color found and the lighter shades are the Ivy Gold overspray. (Repaint was dark green)
The original poster was looking for a color sample for EARLY October and this would qualify as late October, very early November. The color sample of what I earlier referred to as salmon, I suppose we can call light red oxide but I think it has a pinkish hue in person (so to me, more like salmon). On my monitor, it looks JUST LIKE the color I see in person. Photo was taken outdoors in natural light, no flash. FWIW, another fender I have dated December has much the same color on the underside, at least what you can make out of it. It is no where near as clean as the pictured examples I have included below.
I find at least 5 date stamps on every original 67 fender I have (3 originals) and only 1 (date?) stamping found (only on the fender lip) of both of the 2 Ford Service replacements I have on hand. One of the service replacements is a "used", later (1990's) black one and the other is an April of '81 shipping label dated, red oxide version, that hasn't been installed before.