You may be onto something there. I just re-read it and it can easily be parts of Final Crisis.
The Legionnaires that went back are from different times. That is why we saw Sensor Girl and Karate Kid together. And all the rumors of Barry Allen coming back? Well the Legion did save him in this issue. He may not be dead anymore but I don't think he will be returning to the 20th century.
Also is Captain Comet going to show up in the 31st century? He's another IMO that fits the Legion better than most 20th century SUPER-heroes.
"Quislet says: Have a nice Crisis!"
Good eye!