What year is it again? Hard telling from the headliners this summer. The Beach Boys drew 1,300 people to the Deep Water Amphitheater last month — one of the strongest crowds yet of seven classic rock shows booked there. The Creedence Clearwater show Saturday is on track to bring 1,000 people. At the Town Toyota Center, more than 1,200 raised their Alefest glasses to Kansas. Heart’s October show is half sold already.