OK, I have a harness off an 05. It seems that even though the kit comes with a new harness, 05 and up are pre wired from what I can tell.
The harness has the 4 indicator lights, the large cinnector going to the main harness, and three other connectors. A 2 wire (orange and gray wires) another 2 wire ( red and green with red tracer) and a 3 wire (red with blue tracer, brown, and purple)
I've installed a few tachs, and the kit comes with a harness that is exactly the same as what't in the 05's and up, and the single wire they want you to tap into a connector under the tank. I have never had to run the single wire, and don't install the harness at this point, so this should be the right harness. I figure they just went with one part for all production being the Speedmaster comes with a tach standard, and you can upgrade the America.
It's brand new, and yours if you want it. I can ship it to ya on monday........
Pete