Cliff, the hammer is normally a part of the lock, or trigger mechanism as you called it. You can sometimes purchase hammers separately, but not always. If that rifle kit came with a cheap lock, you might want to consider purchasing an entirely different lock. Take a look at the inner surface of the lock plate, and you might find the manufacturer's name stamped there. You have to get a hammer that is of the same brand as the lock or it will not index correctly in relation to the nipple. When that happens, the hammer may not be far enough off of the nipple to be able to cap the gun when it is at half-cock, which is a huge safety concern. This can occur even if you do get the same brand of hammer, as the machining of the parts can result in the index changing a little bit. The better locks are manufactured by L&R, Lyman, and Siler. You can also purchase top-of-the-line locks that are individually crafted by some very fine craftsmen like Jim Chambers or R. E. Davis.
Front and rear sights can be purchased individually, so you should have no trouble finding an adequate front sight, just be sure to measure the front dovetail correctly.
As for a mentor, I have not built an entire muzzleloader from a kit, but I can tell you that I've spent quite a bit of time fixing the little details on both factory and kit guns when they refuse to work properly.
As mentioned, Dixie Gun Works (
www.dixiegunworks.com) is a good source for parts and components as well as these fine vendors:
October Country
http://www.octobercountry.com
Track of the Wolf
http://www.trackofthewolf.com
