That dog's head grip is a Hopkins and Allen.
Next question would be if anyone has seen one of these before. Because of the nickled barrel and unmatched frame.cylinder, I'm with RJay that is may be a "Frankengun". Even if it is, it's kind of neat.
BTW, whats the barrel length? If it's under 16", it could be trouble as it would fall under the NFA regulations (Even if it is an antique).
added: I was just looking at the buttstock again. Are there any kinds of marks on it or the buttplate? I ask because that method of attachment looks like what S&W used. If it happens to be S&W, there is definitely value in it by itself.