Is it Possible I'm Ahead Here?

[Renaud Desferet]

In a made hand vs made hand confrontation, then innocuous cards are certainly a good reason to fold after showing considerable strength.
However, you should always consider the possibility of busted draws that put a little action on the flop, went passive on turn and bluff raised the river.
Here 67 is a fairly good postflop candidate, and 67s is playable by many MPs preflop. I understand that a bluff river raise with a missed draw is not a typical play, but it does happen regularly.
Besides, the number of made hands that typically raise the river are quite limited.
I think it is closer than what you think.