The tidbit that the grey version is newer than the black one is on Rik's site, especially this part: "Interesting note: the second wasn't supposed to be gray, someone accidently trans-posed 2 numbers on the paperwork where the Pantone color code was listed (it was supposed to be the same black color)"
Yes, a recording of the game on ama/pro would be useful =) I can determine MCU speed change by sound pitch.