Something old-fashioned: His hat's a museum piece(1950s+)
The Dictionary of American Slang, Fourth Edition by Barbara Ann Kipfer, PhD. and Robert L. Chapman, Ph.D. Copyright (C) 2007 by HarperCollins Publishers. Cite This Source
Idioms and Phrases with museum-piece
An elderly or old-fashioned item or person, as in When are you going to sell that museum piece of a car? or Aunt Jane comes from another era—she's a real museum piece. This expression originated about 1900 for an article valuable enough for museum display but began to be used disparagingly from about 1915.