If you have an account that was previously EVER in RSC, and you now make him members he will have the same stats he did last time he was logged in RSC.
I remembered an old account name, got them to reset the password, and I logged on to 60 att 50 def and 40 strength RSC staker.
BUT!
If you use an RS2 account that never saw RSC you will be level 3, your RS2 items and skills dont go to RSC.