Where can I find internal plates that are put over connectors...

Hello,

So recently I bought a second hand iPhone wich needed a new battery...

So I thought this was an easy fix, but when I openend the phone i saw that there were some parts missing... The parts are not realy needed for the phone to work, but I would still like to put them back in... I'm looking for those metal plates that they put over connectors to keep them all in place...