OpenSCAD version of OpenX Carriage Arm

I love Buback's OpenX Carriage, but wanted to modify the arm on the back. Before making modifications I wanted to redo this piece in OpenSCAD. I believe this is the exact same dimensions as the original. Uses nophead's polyholes routine too.

Edit: Added a v2 version that adds some overlaps on the difference regions so it renders ok when rendering with the F5 key.