No Harry Kim shouldn't have, she was a complete wreck. It would have been taking advantage of her so newly released from Borg-dom.
The thing that we all know though is that Harry didn't refuse her out of not wanting to take advantage (which would be manly), he refused her out of terror.
BUT.. he should have tried to take her up on this offer later, when she was healthier.
"So 7.. you know that time you asked me if I wanted to copulate? Well.."
But he is waaaay to wussy to do it.