last May, got stopped doing 78 in a 35.  (missed seeing the sign slowing down from 55)...
anyways, asked to see the calibration records on the radar gun and was told I could subpena them.  Then asked to see the serial number of the radar gun and the vehicle VIN number to be sure that they were the same on what I would be subpenaing.  Was told that I had no right to see those by the officer.  I argued, he refused.
Went to court, and subpenaed the audio tape.  Case was thrown out by a very mad judge  ( mad at the officer for allowing me to get off ).  I left, and have since slowed down somewhat.