I think that minor 2, 3, and 6 are not implied in Nashville notation. The 2 is major in practically every song Hank Williams wrote, where it functions as the V of V. It is often a dominant 7 chord, or it can be if you want it to.

Hey, Good Looking is in C, but there is a D that resolves to the G in the bridge, just before it comes back to the C in the verse. This situation comes up in practically every song that Hank wrote. This chord change continues to be found in country songs up until the present, for instance, I Love This Bar by Toby Keith.