LOL, yes.
Rocker panels are the lower panels of a vehicle body, be it car or truck. Look at a vehicle and the lower parts of a car body just on the curve as it goes under teh vehicle.
Here's a place where you can buy weld in replacements. Seriously, think of the lip under the level of a car door, just before it goes under a car.
vny!://www.rustrepair.com/Rocker_panel.htm
'Rock sliders' aka 'Nerf Bars' proctect rocker panels, bottom of cab bodies, doors, etc.
vny!://en.wikipedia.org/wiki/Rock_sliders
[img alt="vny!://www.marlincrawler.com/images/nerf_install.jpg" src="vny!://www.marlincrawler.com/images/nerf_install.jpg"]
Note: This is not my vehicle, and I borrowed this pic from www.marlincrawler.com