Driver Qualification Files must be produced on demand or you are in violation of 391.51. Producing these documents after completion of the review does not negate a violation.
Driver Qualification Files relate to the class of a vehicle, not the type of license a driver possesses. Per 49 CFR Part 391, you must maintain Driver Qualification Files for anyone who operates a Commercial Motor Vehicle (CMV). In 49 CFR Part 309.5 a CMV is defined as a vehicle involved in interstate commerce with a gross vehicle weight rating or gross combination weight rating of 10,001 pounds or more, or one that is designed to transport more than 8 people for hire or more than 15 people not for hire, or a vehicle that transports hazardous materials in a quantity that requires placards.
As an owner-operator, you are responsible for both employer and employee requirements, since you are both the driver and the motor carrier. There are requirements that you as the driver must meet (have a current medical card, driver’s license, etc.) and other requirements that an employer must meet (e.g. document maintenance, random drug testing program participation).