Ball Python overheating?

I just got a 3ft male ball python from a guy who didnt want him anymore. He came with a hand built terrarium, supplies, etc.. On the terrarium, 120 gallons, there is a hole with screen cut out where a heat lamp is to be placed. But the thing is, it is directly in the center of the top instead of off to the side. So my question is, is it possible that Voltaire (snakes name ) is overheating? I havent had the chance to get a thermometer yet. I've only had him a couple of days.

He had been living in a 20 gallon tank, but the guy who had him gave me the option of the larger one, and I took that.

Can't say, based on the information provided - but your best bet is to use some sort of temp controller; and, if that device doesn't have a thermometer that shows the actual temperature, get one of those, too.

I really like my temp gun from Proexotics: http://www.proexotics.com/store/home.php?cat=248

It's really easy to get accurate readings with it, I would not have the heat lamp in the middle of the cage, I would also look into getting an Under Tank Heater. I love the Ultratherm brand, but for any heating source, it is good to have a thermostat to keep from overheating the snake in case something goes wrong.

I would also recommend getting a Under Tank Heater and a thermostat.
Snakes use the belly heat to digest their food.