never ruined my dt's chain and sprocket dude! if its gonna mess anything up it will be fork seals fork setting the wheelie down wrong! if you clutch it up its not affecting the chain and sprocket in any way :D
I thought its worst for the sprockets and chain if you clutch it up xD, since you then rev the engine up high and then BAM the power goes over from the engine to the sprocket.
If you just pull the trottle to get it up, You have constant power from the engine to the sprocket, and when you pull the throttle you just apply a bit more power to the sprocket.
Instead of going from no power on the front sprocket and straight to all the power the bike has xD.