here it is in the constitution:
Amendment IV
The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and no warrants shall issue, but upon probable cause, supported by oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized.
To me, that means that if it wasnt clearly stated in the warrant that they were looking for pirated software then they cant do shit about it.
Again, a good lawyer will prove this to be true