If it is rounded, generally fiberglass. Too much labor to round aluminum. It might be some plastic something. Might remove a screw or two, and see look at the hole and try to and determine. What you have mentioned here is Grey Wolf, and Wolf Pack. No year, or model. Might help to be a little more specific. Also what are you asking? Cracks that need to be repaired? Replacement? Removal?
Sometimes when you tell the whole story, you get better answers, especially on here.
2012 Ford F250 ext. Cab 4x4
2002 Jeep Wrangler Sahara
2008 Yamaha V-Star 650 Classic
2008 Work and Play 18LT