Plasyic Liners
Stay away from the plastic liners. With very little use they are great for rubbing all the paint off areas of your pickup bed. Next thing you know bed is rusted and needs help.
Spray on liners are best. You can drill the holes for your hitch first. On a good spray job, the holes will be nice and clean to reinstall the bolts. They should protect holes when spraying liner.
Just get rid of those plastic liners, my bed has many rusted spots, thanks to a long gone liner.