It uses 2 Alnico V magnets, one in the top coil, and one in the bottom.
The cobalt steel magnets are weak and discharge after a while. That's why everyone stopped using them. They are also huge. The Charlie Cristian magnets were bigger than the pickup.
When I examined Mungi's pickup, the magnet read about 1,000 Gauss, so that puts it in the Alnico V range.