On-sale date from copyright registration.
Letters credit from Todd Klein via his Klein Letters blog (18 September 2016, http://kleinletters.com/Blog/ira-schnapp-in-worlds-finest-comics-part-1/).
Time travel story.
Though we briefly credited Wayne Boring with the Superman figures, due to an error report from Keith Chandler, the consensus of the members of the GCD Main list was that Mortimer was swiping or imitating Boring.
Green Arrow has red hat.