Last night it was a bit warmer out and I took some time to work on the mower.
The first thing I did was take the motor apart. I want to drill and tap the face of the motor so I can just mount it flat against the mower frame. So, I needed to know if there would be enough material to screw into, and if the screws could protrude into the motor at all without hitting anything. The picture shows the flange that will be facing downward. I didn't measure the exact thickness, but it should be just fine.
The motor housing and brushes also looked in good shape. There appears to be plenty of meat left on the brushes. It also seems to be fairly clean.