If you are using a Fab shop to make the boards they will only want the Gerber files as they are exported (no changes). If by some chance they want SVG or PDF versions then you will need to ask them what they want (normally the mirroring is for toner transfer and similar methods used at home).
I have never had issues with silkscreen being larger than the board. I think this is because they mill the boards after they are silk-screened.