2-20 Spread Limit: Hit Double Gut shot on the River. Best value?

[SuitedSixes]

I don't remember the pot specifics, but I flopped a DGS on the flop.

I checked and the CO took the lead in the hand with the button (passive calling station type) calling behind and me calling on both the flop and river.

I hit my draw on the river with a 2, and led out for the max $20 which caused the CO to call and the button to fold.

Did I miss value by suddenly leading (although the draw was decptive)? In the case of an aggressive bettor, and willing caller, did I miss a bet or even two with my river bet?