94 sportsman 400 newbie broken piston

just got a 400 sportsman said needed a carb cleaning well the was wrong found piston busted after removing jug found no pieces around the crank but the main question is there suppose to be oil in the crank area and read about a sump oil found a dipstick that unscrews but have no ideal what it is and being a 2 stroke is that why there is no oil in the crank area. needing to find out if worth fixing
thanks