Is it required to perform Istibra' before marrying a slave girl (amah) who was purchased and then freed before Istibra' was observed?

Primary text

If a man purchases a slave girl and frees her before observing Istibra', it is not permissible for him to marry her or marry her off until Istibra' has been completed. This obligation is not nullified by the act of freeing her, as the requirement was already established.