They may have some big ballas that will chine in but I know La'Burge used to charge $20 a foot to dock there overnight, but they would rather comp you than charge you.
Soo if you have some points that may work for you.
Be careful leaving the concert going back to dock, whole lotta drunk people making a mad dash to boat launch. IMO it's like running the gauntlet of death with a bunch of trashy drunk rednecks trying to get home before the ol'lady passes out from drinking too much Malibu and Boones Farm Strawbeery Hill all day.