It's difficult to judge a muzzle loader solely by it's cosmetic appearance because there could always be unseen issues. However, $100 is a very fair price and even if the barrel isn't perfect, the rest of the gun should be worth it alone.
The older TC flintlocks do have hammer geometry that many people, [even TC] admits was less than optimal. The hammer was shorter than the newly redesigned one that replaced it, and many say that they eat up flints quite rapidly. Other than that they do function well, and if you experience any extreme problems, it can be sent in to TC for a hammer replacement. It's not an automatic free hammer replacement, but often it does get replaced for free, especially if you bring it to the attention of the service manager or experience continuing problems, or you can just simply pay for the new hammer.
Everyone compliments the function of the new hammer design and there may be a redesigned vent liner for it as well. It depends on how old the gun is.
TC has the best lifetime warranty and customer service of any muzzle loader outfit in the world, period. They will replace just about anything for free, just send the item in to them and they will pay for the return shipping. And the warranty even extends to used guns.
It sounds like it's worth the money, happy hunting.