Hi gtman,
The Lawn King is every bit the same as a standard Scott Bonnar machine of the time except for the Pram Bar and that it had a 2.0 HP engine fitted opposed to a 3.0 HP power plant. It was basically made as a special machine to be sold through various Hardware chain stores so as to be different to the normal green coloured units.
Rest assured there are no technical differences between the two versions and to use a good comparison, think of the Commodore vs Toyota Lexen scenario, made in the same plant on the same production line at Elizabeth, but having different badges on it and some slight cosmetic changes.
Cheers,
BB