On page 49, you will find:
Google is your friend.FIREARMS IN VEHICLES
Any person, except a convicted felon, may transport in a motor vehicle a rifle, shotgun or pistol, open and unloaded, at any time. For purposes of this section “open” means the firearm is transported in plain view, in a case designed for carrying firearms, which case is wholly or partially visible, in a gun rack mounted in the vehicle, in an exterior locked compartment or a trunk of a vehicle.
Any person, except a convicted felon, may transport in a motor vehicle a rifle or shotgun concealed behind a seat of the vehicle or within the interior of the vehicle provided the rifle or shotgun is not clip, magazine or chamber loaded. The authority to transport a clip or magazine loaded rifle or shotgun shall be pursuant to Section 1289.13 of this title.
Any person who is the operator of a vehicle or is a passenger in any vehicle wherein another person who is licensed pursuant to the Oklahoma Self-Defense Act, Sections 1 through 26 of this act, to carry a concealed handgun and is carrying a concealed handgun or has concealed the handgun in such vehicle, shall not be deemed in violation of the provisions of this section provided the licensee is in or near the vehicle.