Mark,
I don't know about Company G, but according to the Busey and Martin book, Company F was disbanded on 23 May 1863 and all the personnel were assigned to Company E. However, the regiment also had a Company L so it entered the Gettysburg battle with the usual 10 companies. Incidentally, A. J. McNeill of Company G was reported captured on July 3. The addendum to the official records also notes that Company B had eight men and one officer captured, while Company K had two men killed and 19 captured in this fight. Tom