I don’t think they were instructed because Matthias simply falls off the map in Scripture, never to be heard of again, and Jesus comes along and knocks Saul off his horse and voila, another apostle.
It’s clear that Paul was God’s choice, not Matthias.
Nicely put, anyway! :-)
But what about Bartholomew? Didn’t he “fall off the map in Scripture”? Thaddeus? Andrew?
Yep...no question