Question for those who have built the trumpeter M1A2

If you built the Trumpeter M1A2, was your GPS box (the gunner’s main sight) a completely terrible fit? Piece C57 in my kit has the wrong pegs, but worse, it’s sides don’t fit flush on the turret top, because the lower edges are jagged, instead of flat.

Is there some replacement piece in the kit that I don’t notice? I’ve looked through the box. The piece is obviously not mismolded – the lines are very clean, though completely wrong.

Any thoughts? If your piece was the same as mine, how did you fit it? Cutting off the pegs and sanding down the lower edges to be flat? Where exactly does the box fit onto the hole in the turret top?

Any help appreciated. I’m an M1 newbie. Thanks!