Commanders did come with a plastic engine skid unless the skid plate option was ordered. The fuel tank has a metal tray that looks like a skid plate. Unless it has an extension on the front with 2 studs for the transfer case skid to mount, its just the tray, not the fuel tank skid.
The OEM skids are the ones to get, then the following:
4xguard or steel armadillo
Belly skid - protects the cat converters
4xguard makes rear skids and rock rails if you are getting serious