Even if it is not expunged, one does not need to provide police report. And court often only expunged court record not police records because police record is not open to the public. Sometimes a judge can order police to also expunge police inetrnal records. But if FBI already got the poloice repoort, no judge of any state court has power to order FBI around.
IO can ask you to bring it. Whether you bring or not - up to you. If you dont bring it you need to give an explanation. Explanation like "I didnt bring it to interview because I dont need to provide it" or explanation like "I did my best to get it but it was sealed/expunged and here is paper to confirm it" give different impression of the candidate.
Police reports can be accessible if they are not expunged/sealed - this depends on State law. In WA they are not public so you can not get non-conviciton arrest record, but i believe in CA one can go to sheriffs office and take a ceritfied copy of his arrest records even if charges were dismissed.
FBI will not have a misdemeanor arrest report. They can have info about the arrest but not the police report.