DG Rally wheels are 15" x 6" Corvette wheels produced in January and early February 67. I have never seen any 14" wheels coded DG.
1967 Corvette 15x6 rally wheels are coded "DC
Actually there were both DG and DC 15X6 67 corvette rally wheel and believe most of the DG wheels were very early wheels but they are the same wheel, just with different letters. The DG wheel was also used on station wagons from 1967-70 according to JohnZ. And yes, there was a DG 14" rally wheel and have seen them both advertised and at flea markets. So in reality, everyone was correct......
Actually the DG wheels showed up on the January February 67 cars. I have a 67 Big Block Coupe that has the original spare (DG code) in the spare tire tub, and my car body is dated mid February with most of the other components of the car dated late January 67.