Yes, essentially. This is a technique called wet-into-wet where both sides of the paper are wet and then the watercolor is done into the wet surface. It removes the sizing from the paper and allows the paper to better absorb the color and creates a certain look once dried. Wetting the back of the paper helps the paper dry more consistently so it dries taut and flat and also prevents the dry back from pulling the pigment further into the paper.
I am not a watercolor expert so if I am wrong, someone correct me. It's funny though, I have taken many water color classes at various schools and with various teachers and not one has ever had us wet both sides of the paper!
But, it is a well-known technique. I have read that you should not wet the back side of a very heavy watercolor paper (300 pound) because it will dry faster than the front. You also want to try to wet both sides evenly. Some artists soak the paper in a tub of water then remove the excess.