Yes that's the engine Model number.
They dont have a Mower name that i am aware of.
Masport put out a Iron Horse mower with a later D500 series engine and called them "President"
Some of The earlier models were called "Rotacuts"
The black and white picture is a illustration of the first Rotacut where the grass is expelled from in front of the side wheel.
The Orange and Green Mower shows the very first catcher ever made( from the 100 years Masport book)

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