alot of mad catz stuff i have taken apart has been held together at the edges using the plastic tabs and groves method, if you squeeze the controller from the edges you might see a seperation with gaps and no gaps, if you can seperate it enopugh a thin standard screw driver can work its way in there to pop a few tabs, your generally going to break some (i almost always do) but you dont need them all to be intact for it to go back together, just most.
they will hide alot of screws too, if theres a way to get the front cover off without damaging any sticks you might check under it first