Do I need baking powder/baking soda for my flourless corn bread?
I assume from the ingredients you didn't end up making a corn flatbread. The raising agents will give some rise even without gluten from the flour to form a structure, and the egg will help bind the cornmeal into its raised shape. But its probably rather crumbly (the similar cornbread I make is quite crumbly even with the flour). 

One important point though: if they (and you) liked what you made before, I suggest you don't change it.