Lester as a Legionnaire? Never, no way. His ego was so hurt by their rejection that he will surely have sped off in his spiffy Spiffanymobile to found a villainous group, dedicated to fighting the Legion and extracting revenge.
He certainly would not associate with those trailer trash, low life thugs in the Fata Five.
He may have linked up with Leland McCauley's bratty young son, featured in a Superboy & Legion of SH book way back when.