(Gilbert3, Jacob2, Frederick1) is saying that Gilbert is son of Jacob and Jacob is the son of Frederick. I wanted to make certain a reader would know which Gilbert because there were more than one. I only have records for the three brothers mentioned.
If you send me an email request, I can furnish you the contact info for the person who did the research for me at the National Archives. I'm not going to post his email address on genforum. He charged about $40/hr in 2008. An hour is what it takes him for one Civil War soldier.