No, your basis does not change. It's still $6,000.
This is not a rollover from a designated Roth account. A designated Roth account is an account in a qualified retirement plan like a 401(k). A Roth IRA is not a designated Roth account. Even if the $6,000 contribution had been made to a designated Roth account, the earnings in that account are not part of the investment in the contract. The investment in the contract is $6,000, the amount you paid into it.
The only time that gains are treated as investment in the contract is when the investment is in a designated Roth account in a qualified retirement plan like a 401(k), you've reached age 59½ or become disabled and have had the designated Roth account for at least 5 years (making all distributions from this account tax-free qualified distributions) and you roll the money over to a Roth IRA.
