We're glad the Gravely Pro-Stance is cutting well for you. The design of the earlier Gravely Pro-Stance models was to have the user stand in the middle of the unit with a low center of gravity. This helped with hillside stability and helped the user have a better view of the surroundings while running the unit. Gravely did not make an extended platform for this unit. I'm not sure about the two metal studs you are referring to, but since this was a used mower, it might be that the owner put them on for a specific purpose. The factory Pro-Stance units had raised metal pieces on each outside edge of the foot platform so the user could rest their feet against them for stability, but I'm not sure if that is what you are referring to.
Hope this helps. Thanks.