Glenda,
I can only speak from my own experience but I had Alan and Jim do my great grandfathers and what a pleasant surprise I had. I had some of his material and for years thought I had all that there was to be had. Once I contacted Jim Martin to do the job and he turned his hounds loose on it they did not give up. I must tell you that most of it is pension affidavits and appeals etc. but it sure filled in many of the missing holes. I have enjoyed reading this material beyond belief. I am very familar with the regimental history and the members of the regiment by name for the most part. So when I read the affidavits that they submitted on behalf of Granpa ALex I feel like I am among old friends.
I can't tell you that you will get this much material concerning your ancestor, but I am sure that the Guys will do a grand job of obtaining all that there is to get. I am aware that some records are longer than others but I am glad I went for it so to speak. Good luck in your quest.
Frank Campo