MCL 324.504 provides that the DNR "shall not promulgate or enforce a rule that prohibits an individual who is licensed or exempt from licensure under 1927 PA 372, MCL 28.421 to 28.435, from carrying a pistol in compliance with that act, whether concealed or otherwise, on property under the control of the department." They have decided that said licensure means a CPL, but not the license to purchase, carry, possess, or transport a pistol described in
MCL 28.422.
As far as a duty to ID goes: so long as you're not carrying concealed, they can piss up a rope.
I could be mistaken, but I do not believe there would be a duty to disclose or ID for a range master anyway, although there would be if stopped by a conservation officer while carrying concealed.