To replace or repair slot destroyed screws. The gun in the picture has an over widened screw slots on all the screws except one replacement.
Yes it could be replaced and re engraved though it is a little past trying to correct it. The problem I see is this, the gun is one hundred and fifty years old made by a top London maker the screw is original to the gun and seeing that a gun is only original once so as the gun functions perfectly well as the screw is so I decided that if I replaced it it would be to make me feel better not the gun work better, therefore I decided to leave well alone it may not suit other people so am I right or wrong?
This is the replacement because it was missing when I purchased the gun though I do see it as a wart I would sooner have had the broken screw now looking at it using hind sight.