The problem with that thought is even if one were quite skilled to start with. it may still take years of developing that skill to get to high quality level... the thought that one can just learn to do it so quickly is ludicrous.
Who said anything about quickly?
I learned to do a lot of stuff from books, but mostly, by doing, and re-doing stuff until I was satisfied with the results.
Start with some basic file and sandpaper finishing, and work towards it.
Like I said, it'll never be more than a refinished gun, so it's main value is in the shooting. Money spent on making it original won't likely ever come back to the guy who spent it. The original milling marks and the original markings, they ain't coming back ever. Though there ARE sources for just about any stamp you might wish to forge-reproduce-duplicate, if you spend enough time and money looking.
Polish and rust blue a couple Cooey's and if nothing else, you learn to appreciate the work involved and the time that is on the table when the bill comes due to get someone else to do it.
I will suggest that a fella could do a lot worse than to start by watching some of the Clickspring videos on YouTube. He makes and case hardens files, does heat bluing of screws (directly applicable to the straw colors on the Luger springs, etc.) and a bunch of other hand finishing work.
Doing the whole gun will take hours of work, but sitting down and doing one piece, then the next, each evening for a while, is a lot less like punishment.
Here's what I know to be true.
A flat surface that you wish to remain flat, requires a firm or hard backing to the abrasive paper. Blurred over edges look like hell and are so eye catching.
Pick a backing material that suits the work. I have used hard and soft rubber for curved surfaces, blocks of plexiglass for flat ones. Have wrapped abrasive paper around files or any other convenient shaped object as well.
You need to pay attention to the details, but step away once in a while and return to the work. Staring at it up close for a while, makes you hyper critical as you have time to see EVERY little imperfection, some of which, you won't live long enough to remove. Trust me when I say that as the guy doing the polishing, you will see EVERY little thing wrong, it's because you spent the last hour staring at it, not because it is really wrong!
Buffing wheels have their place in the grand scheme, but polishing up parts that are supposed to look like they have nice smooth curves and edges that are straight, isn't that place. Seriously. You can do more damage in less time with a buffing wheel, than with almost any other tool you might choose to use except maybe a cutting torch or angle grinder. Skip the 'speed' tools.