As noted above heat treating is a critical consideration so the following assumes they're either not he treated at all or you properly anneal them first.
That said, certainly you can recurve the bars. That's how they were made in the first place. It's also how we saved crash damaged bars all the time, before everybody became paranoid about product liability lawsuits.
The key is to properly support the bar especially at the fulcrum of whatever you're using for leverage so you don't kink it, or produce a concentrated local bend. Since you're only talking about a slight change the curvature you should be fine as long as you're careful.