I don't think flags generally carry date or timestamps. Probably some other extensions by LoyceV could have data on that but based on the forum's interface alone I don't think flags come with dates. Normal trust tags come with dates even if you don't add a reference link. LoyceV also has a data collection on that and it's pretty much why I guessed he should probably have one on this too.
However generally the flags are usually created shortly after what happens on a thread so it's usually within same date window.