How to tell if calibration has worked?

[EricThomson]

I am working on calibration as discussed here: http://www.portugueslab.com/stytra/userguide/4_calibration.html#calibration

The red dots in the calibration window show up rotated 180 degrees from the dots in the camera window. Is this OK? Overall the topology of the dots seems to match, modulo the rotation. How can we tell by eye if the calibration worked? Screenshot is attached.