Mark, the 6'10" - 7' refers to the length of the rod. It was written like that because that's what the blank said, since the guy who sold blanks didn't know what exact length would be after adding the grip and reel seat.

I have no idea, however, what the #12F refers to. Anyone?

Unfortunately, it's looking like I have to cancel on the fish-in. I'll know for sure within a few days but I don't think I'll be there. It would have been great to meet you!