I'm not quite sure how feasible that would be.
There are usually two standard ways of detecting IRCops on most networks.
1) /whois
2) /who
Either method would require mIRC to perform a /whois on everybody in a given channel ... or perform a /who on a channel when you first enter it.
In larger channels, that is not feasible and may freeze up mIRC for a few seconds. Additionally, not all networks allow normal users to request a /who on an entire channel. Webnet would be one of them I believe.
It's much easier to obtain a script to accomplish what you want. =)
