do step bars help prevent rust?

I know I'm probably making way to big a deal out of this. The bolts are seized and before I bust out the plasma cutter I'm hoping someone can confirm the mounts are aftermarket and not critical to the frame. I'm thinking they are aftermarket as one of them say PASS FRONT stamped into the metal. Can someone with a similar truck confirm these are part of the "Nerf Bar"

 

My Nerf Bar hooked up to what was on the frame to begin with. I would not cut anything but the bolts off.

 

Interesting...the brackets hang down a bit and look a little out of place, that's why I thought they were aftermarket.

Anyone out there in Tacoland that can take a peek at their 01-04 cab mounts to see if the brackets are factory installed?