I should have my order in a few days, and I'll know what the part number I posted was.
Diesel and steam do have different wire colors and pin assignments, for reasons that I'll never fully understand. However, as long as you ring them out, the colors are somewhat moot when you're using them for TMCC upgrades.
The interesting thing about AG-0000039 vs. AG-0000066 is that they are both MSRP $8, seems odd that one would come with wires and one without.
Here's what I find for the two:
First, from the 4-4-0 General parts listing.
7.) PCboard(green) AG-0000066 8.00 (w/blackfemale10pinplug) ( notchedcornersonrearofboard)
Next, from the RK S-2 Turbine 6-8-6
27.) PC board (10 pin)( female ) AG-0000039 8.00
Sounds like the one I specified may have some notches to make it fit into the General. When I upgraded a General, I had to trim the board to make it fit, so that makes sense.