As others have said, there is no amount of money you can put into it that will make it worth more than what you end up having in the gun, and that gap will only grow the more you add. That being said, nobody here will be looking at that gun nor shooting it, so if you set value aside, you need to ask yourself what do you want it to look like? If you don't like the nickel now, then refinish it. I had a similar situation with an original 1873 made in 1887 that had been reblued and poorly at that. I had the frame and associated parts case colored. I'll never get back what I put into it, but I am very glad I did the job. Now I love taking it out and shooting it, and folks love the way it looks. If the colt were mine, I would probably spend (waste) the money getting it back to original. Sometimes having the collector's value taken out of your hands can be a good thing. It really comes down to what you want to do with it, though.