@swum, not necessarily,
even F2 reg Auto seeds will be subject to different phenotypes.
it also depends on so much. was it an auto male that you pollinated a photo fem? or was it a photo male that pollinated an auto fem? depending which of the plants has the most dominant traits will depend on what traits the offspring gravitate towards.
and what you are referring to is called Hybrid Vigor... most bagseed tend to express rapid healthy growth and are known to have this vigor.
well bred plants from reputable breeders also exhibit this trait, but it does not often express itself in later generations starting from F3.
successful back crossing with the original parents can often bring back this trait in your offspring.