Yes, the difference between a regular distribution and a return of contribution is the method used to take the money out of the IRA, indicated by the coding on the Form 1099-R reporting the distribution. A return of contribution is most often used by those who make an excess contribution to an IRA, but the tax code allows an IRA contribution to be returned before the due date of the corresponding tax return for any reason, not just for excess contributions, to allow the contribution to be treated as never having been made. However, a return of contribution before the due date of the tax return comes with the requirement that the distribution be the amount being returned adjusted for any attributable gain or loss, with the gain being treated as taxable and subject to early-distribution penalty. A return of contribution 'undoes' the original contribution while a regular distribution does not.
With the investments having gained in value, the result would be that more than $6,000 would have to be distributed for the return of $6,000.
