The 0000 steel wool will also work well for removal of light pitting on the barrel/action, if you're rebluing. If it takes more than that, it probably isn't worth trying to remove it. Shoot it with a little oil and use light pressure to buff it out. Be sure to remove all oil before attempting to blue.
On the cold bluing... Cold bluing processes of this nature don't actually blue the steel. They put down a coat of copper on the steel, and blue the copper. If you smell a gun that has been cold blued using this process, you can actually smell the copper in the finish when you're done.
While this is a cheap alternative, and it will give you decent results, it's not a real durable finish. It tends to rub and/or wear off fairly easily, and fades fairly quickly even with multiple coats applied, in my experience.
I used it on one gun... Was an antique Stevens 410 Single Shot that someone had tried refinishing (stock, action, and barrel) with 80 grit sandpaper. It worked well for me in that case as I wanted the natural rust finish back about it, and couldn't find any browning solution the weekend I tackled the project. It protected the steel well and gradually allowed the aged rust finish to rejuvenate over a few years, under the bluing, restoring the gun to a natural finish in much less time than would have been otherwise necessary.
Not saying don't use it... just saying if you want a durable long lasting blued finish, you aren't going to find that in a bottle.
If you have any dents in the stock, you can easily lift those with a damp cottonball and a hot butter knife. Heat the butter knife over the burner on the kitchen stove or a propane torch, lay the damp cottonball over the dent in the wood, and apply the hot knife firmly to it. This forces steam into the wood pores causing the grain to expand, and lifts the dents out of the wood without having to sand deeply to remove them. Results are not always great if the wood grain has been broken, but attempting to lift those where it has been broken will raise the grain to a certain extent, reducing the amount of sanding required to remove the scratch or dent.