How we can detect magnet monopole? How we can distinguish it from electric monopole? If we change E to B and B to -E in Maxwell's equations we get proper equations for charge and current density which we can call them magnetic charge and magnetic current. Even if magnetic monopole exits there is no distinction with electric monopole!
The symmetry between electricity and magnetism, though present in Maxwell's equations, is completely absent in the real world. Electrons have electric charge and disk drives have magnetic domains ... not the other way around. If you tell someone "actually electrons have a magnetic charge and disk drives have electric domains", that person will tell you that you're crazy.
Since things like electrons and bar magnets are readily obtained for our testing purposes, the upshot is that we can easily tell a magnetic monopole from an electric monopole.
More specifically: An electric charge interacting with a magnetic charge looks quite different than two electric charges interacting with each other, or two magnetic charges interacting with each other. So we can set up interactions between the alleged magnetic monopole and some electrons, and that way figure out whether it is truly a magnetic monopole.