Most often, when the trigger plate is taken off, it does not go in all the way, as it was before. I always tap around the edges with a small nylon hammer to seat it. If it's up .0005"(a half a thou) the screws will not be oriented as they were. Never use the screws to draw up the trigger plate.

A technique I was taught by Judson Darrow, long past, but the best gunsmith I ever met, was to take a sharp prick punch, and stamp one spot in the center of the thread end of the screw, that will put a small upset around the impression, and then tighten the screw back down. Alternatively, three prick punched impressions, in a triangle.

It's highly unlikely a screw with a perfect slot was over-tightened to the extent it stretched it. It is only the un-threaded shank that can stretch. Proper fitting threads, in holes don't stretch with hand tools, and the finer the thread, the more it resists deformity.

Screws
 

I haven’t had that problem, we are usually talking about quarter or less of a turn.