Sadly, it's brushed. He tested the RPM's twice using a cheap tach. It's a nice size for any kiddie vehicle project you can think of, but I doubt used ones will be easy to find. I suspect the mowers will last a very long time. I have one and I'm happy with it.
https://www.youtube.com/watch?v=RGEyJ1uGcJQ
4,380 RPM @ 61V = 71 kV
3,130 RPM @ 47V = 67 kV
https://www.youtube.com/watch?v=RGEyJ1uGcJQ
4,380 RPM @ 61V = 71 kV
3,130 RPM @ 47V = 67 kV