Damaged guns are much harder to sell than complete guns, since extent of damage always varies and there is no price guide for damaged guns. I would suggest getting a full percussion hammer back on the gun. You have the base of the original hammer as a good starting place, or guide, for the restorer to work with, and as said by Rich, there are many examples out there on web sites to model the missing portion from. You may also get lucky if you post your needs, and someone may have a similar original hammer in his drawer of junk parts. If not, a close replica can usually be reworked, i.e., filed closer to what your hammer originally looked like, engraved like it, and colored like it.
Your surface is finely pitted, but most restorers can "reasonably" duplicate the roughened surface and color. Yes, it will be noticeable, and it may require the entire lock to be recolored to match with the new hammer better, but the pistol will be MUCH easier to sell if/when complete with a restored hammer. If you decide to go in this direction, you can always start by posting it over on the Contemporary Gun Collecting side for ideas on best way to do it and who might be available to do the work. You won't get rich on this pistol, but you shouldn't lose money, and perhaps you will enjoy keeping it as a family heirloom once it looks better.
Shelby Gallien
