[cfjr2]

I think you should have bet the turn. If you had and he called you can be fairly certain he has a str8 draw or a pair. If villan then bets the river you call and save 1 bet, if villan check raises the river you can call and you are even with the line taken (or fold but I don't like that much as he may bluff into your agressiveness)

so even if my assumption that villan bets the river after your turn bet only happens 10% of the time you still save .1 bet when you lose this - so overall slightly +EV over line taken.

There is the down side if you don't improve on the river but I think it evens out with when you win on the turn if villan folds bottom pair and when you improve to the nut str8.

Once you have a read on a specific villan this would change of course