I had a call (unsolicited) six weeks ago to see if I would be interested in coming back (I left four years ago.) They had already phoned my ex base Captain for a reference, asked when I could start, and what my notice period is. Since then NOTHING. I know of at least one other ex Captain who has had the same treatment in the last few weeks.
My conclusion would be that it is just some list of possible returnees, carried out with FR's usual flair and sensitivity.