IIRC, all K100RS and K1100RS came with 31/11, 2.81. Standard K100, K100RT, K100LT, and 1100 RT, LT, came with 32/11, 2.91. Could be wrong but don't want to get up and look because of turkey hash.
Speedos are always off unless you sent it out to get serviced and calibrated. The guy servicing the unit has to know yer gear. Not unusual to have different FD with a different gear, like a 2.91 on an RS.
Airheads are just as bad. At least ten percent faster than reality. Always thought I was going around eighty. After calibration with 33/11, at 4K, more like 68. R90S. FWIW.