mIRC does not store the information through RAW events or store it at all whatsoever,

ISOP is used to compare regular listed nicks has regular users or users with the SYMBOL @ inclusive in their nick from the server side.

Has you join a channel example #mirc with let's say 50% of users op'ed at no point in time does mIRC store the information anywhere, at most a names list check is performed.

So again mIRC does no store this information and ISOP is used to compare users in your list for which one has symbol @ <"Or equivelant"> in their nick.

Server has this information ready for the client "MIRC" to use.

if $reality > $fiction { set %sanity Sane }
Else { echo -a *voices* }