Since grills are not included, the only stamp that needs to be checked is 73 for a grill since 93 with an F grill is actually cheaper. I did check 73 front and back for any signs of grill with an illuminated 30x jewelers loupe and saw no signs of a grill.
The color for 65 was checked against the Scott Specialized Color Guide for 64 and 65. It does seemed rather absurd to have so many defined colors and to carve out a few as a different major catalog number since we are dealing with primative inks in the color most susceptible to natural light exposure.
I assume the 5 cent Jefferson is brown (76) instead of red brown (75) since 76 is less than a third of the CV of 75. Again, we are to look for a hint of the most unstable color (red) to determine a major catalog number.
Finally, I'm calling the 24 cent Washington lilac (78) instead of red lilac (70) even though it has a slightly higher CV. I just can't see a hint of red, but once again, we're looking for red!