Picatinny Rail Cover (3 Slot)

My attempt to make a cheap 3d printed Magpul XTM rail copy.

Currently the model is very rough. I just did a boolean difference with an oval cylinder on mattroberts' G36 rail.
http://www.thingiverse.com/thing:4757

I will work on the separation for the two ends and come up with a way from them to snap together as well. Texturing is last.

Here is what I am trying to mimic: http://www.cgwgun.com/images/products/MAG410-FDE.gif