That would save it, so if it's perfect nature, perfect Gender, shiny, and has the perfect ability... But had like all 0 in IVs, and you did an EV battle to check, you'd be rather annoyed since it would save. See, the nature, gender, ability, and if it's shiny or not is set when the Egg's created... But IVs are set when it's taken. So if you save before getting the egg, you can try to reset for epic awesome IVs.
B~T: ... Point. =P
Or just battle Pokemon to raise their levels, and make sure to keep track of the EVs they yield. That way, no Rare Candies wasted.
@period - I think you have to save in order to battle, so it will not work out.
