MakerBot Print is our newest print-prepration software, which supports native CAD files and STL assemblies,
allows you to interact with all your printers via the Cloud, and many other exciting new features.
Hate to say it, but I just found one other minor issue. In rightsidemiddle.stl, you missed putting in a hole for the pin that connects it to rightsidebutt.stl. Again, it's something I can drill out, but thought you would want to know the hole is missing.