Ive fitted ones that have the cover sprung so it always covers the keyhole rather than sticking up or flying round . Im assuming thats what Dom means .
Perhaps I have the wrong terminology, but they are those brass strips which are inserted into the timber and are the shape of the keyhole, a sort of inlayed keyhole surround.
I fitted some recently and used the drill press, 2 sizes of bit to suit, reference marks on fence and table as the drawer fronts were all the same size, very sharp chisel to ease down the ridge between the two holes and finally don't tap the escutcheons in the hole, use a clamp to squeeze/pull it in.
Took longer to type than actually do
beejay