ok first, everyone is genetically structured different. the petoral major is one muscle and grows accordingly to the genetic makeup of the individual.
i think what your trying to say is that you think the chest itself will be symetrical in build. well, if you can do that you are a better man than me. in general i would say push-ups are a good exercise but they are not going to make you grow to your fullest potential. i would use them maybe as a finishing move.
as for the lumpy statement, i don't know anyone who has a lumpy chest!