It is a common misconception that traffic officers must show their radar guns upon request of the motorist. This simply isn't true. However, if you choose to dispute your charge, you (or preferably your attorney) can determine all sorts of information about the radar gun including maintenance records, training records, method and frequency of calibration, etc.
You should consult with a criminal defense attorney familiar with these issues. Many can be found here on Avvo.
Best of luck.
Agree with John. In Virginia, law enforcement not required to show readout on RADAR. In fact, in most cases, the police do not even "lock in" the speed. However, some agencies may have a policy regarding whether to show the readout. This issued is typically the same for VASCAR and LIDAR.