No... over the course of about two hours, I slowly added warmer water to the garbage pail he was in until the water he was in was the same temp as the water in the tank (started with it at about 75). Since he's been in the tank, about two more hours, I've slowly raised it to about 77. I figured that would be warm enough for now... seeing as he's been in 69 until now!! That's about two degrees per hour... that's not too radical, is it?
Edit: I should add that he was lying on his side on the bottom of the tank when I was at the house getting him and they said, "He does that quite often... lies on his side like that... and you'd think he's not well, but he's been doing it ever since we got him."
I presumed it wasn't really normal behaviour, but the stress of living in an inappropriate tank/no heat etc.