Xterrible, that pic is of the front tube, which is basically a muffler (expansion chamber). It does nothing for the emissions, as in, it's not a cat.

We don't get many California Emissions vehicles here in Colorado, so I can't say with 100% certainty that this part isn't a cat in the Cali trucks.

But everyone that has a Federal Emissions vehicle, can yank 'em. Just be sure to weld a bung for the sensor at the front there, just like in your pic.