I'm not sure if I’d be worrying about missing out on value, but worrying if I'm ahead.

He’s check raised the flop, and bet more than the pot on the turn. I’d say this shows he has a hand and it’s not a draw.

Question is – is it A7, K7 or 66? He could have any of these hands. But he could also have a lot of other hands containing a 7.

Just call. Any other hand containing a 7, apart from A7 and K7 are drawing to 3 outs. If he checks the river then shove, he’ll probably call with a 7 in his hand, or if he hits an overcard with a good kicker.