The State of Oklahoma hereby recognizes any valid concealed carry weapons permit or license issued by another state.
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... Any person who is twenty-one (21) years of age or older having a valid firearm license from another state may apply for a concealed handgun license in this state immediately upon establishing a residence in this state.
In reading this I'll assume that "person" is exactly what it says with no qualification as to residency in Oklahoma. "May apply" I assume means that a new resident, if they desire, can apply for an OK CCW upon becoming an official resident or they may continue to carry using the CCW from the state that it was issued even if they become an OK resident.