I'm only asking because I don't know, what do the marks on the uppers, above the forward assist, mean? I've seen squares, triangles, arrows, many different symbols but never figured out what they mean. I've seen some people in BST put in the Ad that the AR has a certain mark, I don't believe it would raise or lower value unless it was a Colt mark maybe?
Example: the Square on this upper
Example: the Square on this upper