You dont need to know anything about it to just spot differences between model and refs, its like your normal womens magazine, spot five differences, only here you sont know how many differences are in there
Actually by looking at it again i saw many more differences then first time, will edit with picture in a minute.
EDIT:

White: different shape then on the ref, a less round one too, will save some tris
Purple: differnt shape then on ref, the groove is much deeper and steeper
Yellow: should be flat, it can save a bunch of tris
Dark blue: some missing peices of the RIS on the and of the rail, also the bottom of the rail should have fifferent shape according to ref.
Dark green: should be two bolts there, not one.
Brown: The edge should be sloped, not horizontal as it is
Orange: different shape, different size
Black: dfferent size, should be longer
Light blue: missing screws for attaching to the rail