Visible crew/equipment: At the start, when Colonel Potter walks into post-op to tell Margaret and Hawkeye about the fresh eggs, just as Hawkeye stands up the boom mic can be seen at the top of the screen, before the camera adjusts to the proper height.
Visible crew/equipment: In the kitchen, as Klinger and Winchester banter back and forth, the shadow of the boom mic can be seen in the upper right corner of the shot.
Answer: Even an Army field hospital would have SOME weapons for self-defense if the enemy attacked. What's meant is that it's not a combat outfit, and therefore wouldn't have enough weapons to actually attack anyone. (It's also mentioned a few times that the Officer of the Watch is supposed to carry a pistol at all times, but Hawkeye refuses to do it when he's in charge and Colonels Blake and Potter don't enforce the rule).
Captain Defenestrator