Did Tom Chamberlain meet and comfort the dying Lewis Armistead, as depicted in Civil War Newsthe Gettysburg movie?
No. The Twentieth Maine was back from the main line, in reserve north of Little Round Top but well south of the action, during Pickett’s Charge on the third day of the Battle of Gettysburg. There’s no suggestion that either Joshua Lawrence or Tom Chamberlain left the regiment at this time to participate more closely in the events. Armistead’s reported words, after he crossed the wall on Cemetery Ridge and fell wounded, were reasonably close to those given in the movie, but his comforters did not include Tom Chamberlain. Ron Maxwell (the director of Gettysburg) was well aware of this, but insisted on keeping Tom in the scene for dramatic effect, and to some extent I can see his point as it balances and enhances the final (also fictional, but wonderful!) reunion between Tom and Lawrence.
