> So evidence dated within or near to that time frame is all fair game.
Not after (as in near but after), if one wants to be uber strict. In cases such as this one (when there is a relatively change of nationality, involving changes of jurisdiction) it may be prudent to be (uber) cautious.
Yes. “After” is where potential problems creep in. Not necessarily always or in every case. Sometimes the provenance works out. Sometimes not. In general, though, there are more sources of complication and linguistic corruption.