This is a functional equivalent to the injection molded X-Axis Carriage mount on the Aurora A3 printer with some improvements. It should mount and function exactly the same as the original part. I purchased this 3D Printer early 2016, so older/newer models may be slightly different.
I beefed up the back plate as well as mounting holes for the linear bearings. I tried to eliminate any slop in the original design as well as make the whole structure stronger.
The parts are designed with a .25mm tollerance, so they will fit together very snugly and may require a little sanding/filing on the corners to square them up. I recommend printing this on a slower speed to improve accuracy and help with assembly.
Recat also has a resigned variant of the same carriage: http://www.thingiverse.com/thing:1148159
Highly recommend printing this slower than normal so you get good clean corners and screw holes.
I also suggest infill more than 15% for added strength and top/bottom sides of 1.2mm or more.