The pointers show what's left of the rubber insulators, which probably degraded faster due to the excessive grease inside the gear. As the new part demonstrates, NONE is required inside the white plastic gear.
The metal & nylon gears simply slide up off the shaft. The kit includes grease to lube the central shaft & the outer teeth of the new gear before installation. Reattach the seal plate, & reinstall the motor on the regulator. Push or pull the glass slightly to align the gears so the motor mounting holes will line up. Lube the regulator gears while you have access.
There's also an aftermarket repair kit available from any parts store that deals in MotorMite HELP! parts - it's just the 3 delrin bushings (green pointer), and you stuff them into your gears. Advance charges ~$8 for them, which is a rip-off price. See p.35 of this PDF:
https://www.henrysautomotivewarehouse.com/2017_web.pdfMany people just drop 3 steel nuts in; they'll never wear out. You can also use sections of coil spring cut to length, thick rubber hose with something inside to keep it from collapsing, or even just fill the gears with epoxy.
Also see:
Motor bolts are 5/16" (8mm) 6-point head w/integral washer; 12-24x5/8".