That field has been gone over and over and over an over and over and over....get my point. And, archaeologists went over every shovel full of earth when the thing was built. Artifacts found on the field today are a one in a bazillion chance of luck. All that ugly mess of a building needs is a bulldozer. There hasn't been a glass dome over that field and town for the last 150 years. Remember, Camp Colt was there, there were photo studios, a trolley a dance hall and even an amusement park on the battlefield. Pristine it isn't. Not even close and, there's things that were there during the battle, that will never be brought back. Take the stone quarry that was just behind the Trostle Farm, the Bliss Farm, the Klingle Farm the Heagy Farm as several examples. Not that I'd mind seeing all the trinket shops in town blow up.
The 137th NY performed way, way better than the 20th Maine at Gettysburg. They just didn't have a self promoting blow hard of a Col. leading them. Maybe you should look up the history of the 83rd Pennsylvania too, they make the 20th Maine look like the rookies they were.
There are some very good books out there about the fighting on Culps and Lower Culps Hill. Vincent's Brigade had nothing on those boys at the other end of the line.