No permission required, none asked, no payment made. Both sides took what they wanted, sometimes even if it had little to no military value. After the war, citizens could file claims for damages and losses, but relatively few were paid and then only pennies on the dollar. PM records generally do not have claims in them. Remember Missouri was functionally under martial law and the local PM's were little gods in their area of control. Some were good, some were awful with the full spectrum of honest to crook. Highly political appointments.

see https://www.archives.gov/research/military/civil-war/southern-claims-commission for federal claims. Somewhere in the MO SOS files is a similar document for claims filed against the state that has Unionist claims for both Federal as well as State Militia and Missouri State Guard claims.

JJR