Following its 66th issue in 1970, Uncanny X-Men was cancelled due to low sales. Eight months later, though, Stan Lee decided to revive the title as a reprint series, running old stories from the mid-1960s. This hiatus would last five years, but the X-Men did not completely disappear from the Marvel Universe during this time. The team made occasional guest appearances in other comics, but to avoid confusing new readers, Stan decided that the characters’ costumes should match the ones in the stories being reprinted. Thus, rather than wearing the individual costumes the team had been awarded in Uncanny X-Men #39, they were inexplicably back to wearing their original school uniforms.
Since this was purely a marketing decision, I don’t believe it represents an accurate depiction of what was “really” happening in the Original Marvel Universe. Instead, I maintain that the X-Men continued to wear their individual costumes until the membership shake-up that occurred in Uncanny X-Men #94, when the title went back to printing new stories. Therefore, I decided it would be fun to revise some key pages from this period to show the X-Men the way they should have looked all along.
From Captain America #172:
From Captain America #173:
From Captain America #174:
From Marvel Team-Up #4:
From Marvel Team-Up #23: