Dwight, I have a book titled Confederate Monuments at Gettysburg, by Dr. David Martin. It lists every Confederate monument, tablet, plaque etc. and text, with Dr. Martin's comments as to the units involvement. He promised a Union book to follow. But it doesn't. I emailed Dr. Martin asking if he wrote the follow up, and he was kind enough to return that it is still in the working.
Time is tough.
There is a guide at G'burg that did do the same thing about Union markers. I've seen it as a source.