Skylab I, II, and III Unflown Robbins Silver Medallions

Skylab I, II, and III Unflown Robbins Silver Medallions /I , Serial Numbers 239, 184, and 151 /I , from the collection of astronaut Charles M. Duke, Jr. 35mm, with the mission dates engraved on the reverse. These medallions, though not flown, were made t