The Association of Licensed Battlefield Guides
Try this group or the historian at Gettysburg NMP...they may be able to help.
There is so much written I am sure the story has been told somewhere.
The 6th PA Reserves/35th PA VI did conduct a counterattack after the last failed Confederate attack on 2 July towards the Round Tops. The purpose was to clear the Devil's Den and area of all Confedrate activity.