Hatcheries don't take "extra" eggs just because. Hatchery operations are so tightly regulated that there may be a few thousand, maybe a fews tens of, extra. Normally, this is to cover unexpected incubation mortality.

There are generally strict controls on where eggs and fish can be moved to based on fish health/pathogen concerns. Pretty much if the eggs are on surface water they can't be moved. As with all rules, they can be overridden.

I would lean towards the case that there aren't many eggs to move around.

If those eggs in The Great Lakes are on pathogen free water and if they can provide excellent and detailed pathogen history, then maybe they could be sent back. But, these fish would have been entirely resident, not migrating very far, and would probably bring some really weird genetics and behaviors back.