Yes. Eternity (in its proper meaning) is in God alone, because eternity follows on immutability and, properly speaking, God alone is altogether immutable.
Nevertheless, some receive immutability from Him, and they share in His eternity. Some receive immutability from God in the way of never ceasing to exist.
Moreover, the angels and saints are immutable in being and in operation: "no changing thoughts exist in the Saints" (Augustine, De Trin. xv).