Get-a-Life Boy saysThe more I think about this story, the more emotionally and morally questionable it becomes.
Dialog makes clear that Brainy and the other Legionnaires had every reason to suspect that the clones would self-destruct after 48 hours. Indeed, it looks like these aren't the first such clones they've created.
So...the Legion created clones who would believe they were the originals, knowing that there was a good chance their buddies would die in 48 hours (plus possible other such clones). This seems pretty callous, if not downright cruel.
Then, the Legionnaires sent those clones to an unsuspecting Superboy, not explaining the truth to Supes until well after the poor Boy of Steel had gone through the emotional rollercoaster of meeting his "dead" friends. The Legion could easily have spared Kal that ordeal.
Basically, the whole story is a cheat: characters act in cruel, irrational, and non-characteristic ways just to fool the reader.
This story was written by Cary Bates, whose work I find spotty. Sometimes he hits on a good story; often his plots and characterization are a mess.
