Oklahoma is a godless, lawless place - feel free to do as you please...
Not so .... I have a friend that was in Oklahoma and was headed to my cousins ranch, he had a pistol with the clip in it(loaded magazine and un-chambered)that was in a plastic case inside the center console and 4 rifles that were unloaded.
He got pulled over on a county road and there was a empty can of beer in the back floor board with a couple of drops of beer in it from hours earlier on the ranch.
The result was him being booked into the country jail on "open container with loaded weapon" which upgraded it to a felony charge and he sat in the county jail until the following morning at which time the judge said "This is B.S. you let them go RIGHT NOW!"
In Oklahoma your rifle must be unloaded including magazine while transporting during hunting season and muzzleloaders must be uncapped.
Even if you are on private property you cannot have a loaded gun in the truck and cannot fire out of a vehicle.
The only loaded weapons allowed in the vehicle are those allowed by concealed carry and you must have a permit.