Another original 1963 U.S. Proof Set, still sealed in its Philadelphia Mint mailing envelope. The yellow Treasury envelope remains unopened, with the flap intact and no signs of prior access. It shows the expected age-related creasing and pencil marks, but the Mint seal appears undisturbed. Collectors often prefer these sets untouched, as the proofs inside have never been handled. See photos for the envelope’s wear and markings.