That Marine Bronco art is a little bit fanciful. I doubt any were ever configured such. Air Force OV-10s had M-60s in the sponsons, but some commanders prohibited loading any ammo for them to prevent FACs from going "cowboy" instead of FACing. The normal load was a centerline fuel tank and two rocket pods. Without the tanks, the Bronco had limited loiter/transit time. With them, they were overloaded with any other ordnance. The joke was you could carry bombs, but you'd only have enough range to attack your own airfield.
