Palin, born 1964, is no longer catholic, as an infant she was baptized in the denomination, but left it.
In 1969 her mother was searching for a different denomination, and in 1976 Sarah was baptized in an Assembly of God church, today Palin is a non-denomination Christian.
You may not be familiar of the marks (they are good) left by certain Catholic Sacraments: Baptism, Confirmation and Holy Orders.
Palin, thus, will always be marked as a Catholic whether she is a practicing Catholic or not.