The original didn't match the screw pattern on my MP Select Mini so I altered it based on my printer's measurements. I oversized the holes on the left screws because the original screws installed in my printer were very short and probably wouldn't fit the brace unless i countersunk the hole to one or two layers.
Added a cap to the rod holder as my bearing rod had a slightly rough cut and i didn't want to slice myself on it. I resized the screw holes to match hardware i had on hand. This seems to work well on my printer, but i don't know which other revisions it'd work with.
I'm using it with this x gantry support: http://www.thingiverse.com/thing:2185034
I needed supports with 30% support infill specifically for the left half's lip which reaches over the right half.
After screwing the two halves together you may want to fill the gap with glue of some kind for added rigidity. Mine seems to do well without it but YMMV.