Toro gator blades

I have an older 1989 Toro 2 cycle 21" mower #26682 that has the side discharge chute and the rear bagger. I was looking at the G3 Gator blades #96600 and see that they will replace my orginial high lift blade #62-7700. After checking the Toro parts lookup site I do not see a plug listed for this mower. A label on the chute door states to keep door closed when bagger/side discharge is not in place.

Did this year mower not require a mulching plug or is it not advised to mulch with this...

Toro gator blades