Well from what little I know about Beretta SOs, this is probably a gun you want to think hard about purchasing. I cannot imagine how an SO with the crossbolt can have barrels be loose. There must be enough wear where the crossbolt meets the barrel lugs to require the lugs to be rebuilt. Or someone mucked with gun at one time caused a problem with the barrel fitting.

Make sure you get all the questions answered after the repair (eg., what did they actually did, where is the top lever, etc.)