Leg training does create total body growth by means on the positive hormonal environment from a good leg session not to mention the thickness you will put on your back from stabilizing heavy squats and deadlifts.
That said, if you want to focus on upperbody, by all means do it, but at least do some maintenance leg work. Do not drop leg training all together.
James 1:16-17 ESV
Do not be deceived, my beloved brothers. Every good gift and every perfect gift is from above, coming down from the Father of lights
With God's help...Mens sana in corpore sano