Out of this batch...you got one just slightly below the best I would hope to get out of it. That ding in the handguard being it's only major flaw. I wonder if that happened during the unboxing videos...
If you want it a little more spruced up, but also retain originality...just get a replacment gas tube and stock. I would leave the original furniture, and the gas tube/handguard intact....removing the handguard ferrule can be difficult and it's easy to screw up parts. You could retain the original 'look' and have a nicer appearing gun, while being able to revert back to original in minutes.
As long as these soaked in cosmo, any refinish attempt would likely end up getting buggered up as it sweats out when you shoot it anyway. There are a multitude of replacement stocks out there, you could possibly find an unserialed one.
Personally, now that I know better...I would accept it and it's history as is. You already have the bug, you just don't know it. You will have another SKS soon.