Split into episodes 4 and 5 in syndication:
Mirrorland
Lost and Found
Run time: 9 minutes 40 seconds.
When Gumby loses his coin through one of three mirrors, he begins a search within the virtual images of each. In one of the mirrors, Gumby's reflection assists him. Instructed to do everything backwards in the Mirror Land, Gumby is able to trace the location of his coin.
A shortened version of this episode was named "Lost and Found"