The would do a full post mortem, which would find anything. There is not a 'rape test' as such, but obviously it would show up on an autopsy if someone (male or female) had been raped or sexually assaulted.
I can see how a man can be sexually molested or fondled against his will, but honestly how would you rape a guy ? He would have to be hard of course, and if he was really against having sex with the women Im sure he wouldn't have an erection. Plus what guy would be unable to fight off a women?