The gun isn't that bad. It's just used. I would leave it alone. If you want a new gun, just buy one. As you can see, even good bluing is not particularly durable.
The DIY reblue kits are junk, they are for touch-up bluing only-regardless of what they say on the packaging. The finish is not durable at all, promotes rust, and looks terrible. Of course you will find people who tell you they know the "secret" to applying cold blue. Don't believe them.
If you are going to refinish the gun, use a professional refinisher and do an upgraded finish like nickel or industrial hard chrome.