According to this post showing the
assembly manual, the rear bracket is shown on an angle.
Although you can't see the numbers, they are:
from bracket #1, measurement showing from both holes, to bracket #2,
both holes, are 31.062 + or - .062.
bracket #2 to bracket #3, using inner hole only on bracket #3,
is 27.438 + or - .062.
The measurement on #3 bracket doesn't use the outer hole,
which shows it on the angle.