The RIDGID brand name is licensed to Home Depot by Emerson Electric Company. Emerson owns the Ridge Tool Company - maker of the Ridgid brand plumbing tools.
TTI is the OEM for most (probably all) of the Ridgid brand power tools - and these tools will bear UPC codes with 051667 as the company prefix denoting TTI.
But the Ridgid brand pneumatic nailers appear to come from a different OEM - and bear UPC labels with 648846 as a company prefix - denoting Emerson's Special Products Division.
Some Ridgid brand garden tools that I've seen at Home Depot are made by Ames (UPC prefix 049206)
Some Ridgid brand extension cords that I've seen at Home Depot are made by Cerro Wire (UPC prefix 048243)
Some Ridgid brand holesaws that I've seen at Home Depot are made by RAF Industries (UPC prefix 035781)