It's an autoflower, so unless it is defective you should not have to worry about re-vege. Light does not control this phase-shift for autoflowers.
re-vege will cause new leaves and stems to grow. It'll get taller and the new leaves it grows will look so drastically different, you will certainly notice them. They come out 3-lobed and rounded with no serration type stuff... look weird in a noticeable way.