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.
You got it!
I just uploaded a left handed version.
This was a modification of another thing, so I didn't have the source files. While I had separate meshes for the threads and body; the tools I had didn't have the ability to mirror mesh pieces (Fusion 360 nor 123D). But after several hours of trying different things I found that Cura allowed me to mirror and then save the modified file, which I could then import back into 123D for the merging.
I have not printed this left handed version, so please let me know how it works out for you.