Are stacked NN the second generation of NN?
No.

Kumar, Satish. Neural networks: a classroom approach. Tata McGraw-Hill Education, 2004.:


  The first generation of neural network models employed McCulloch-Pitts TLN type neuron. They were essentially switching networks. The second generation of neural network models employed a smooth sigmoids. The sigmoidal function was motivated by the increase in firing rate of a neuron with the net input, which is saturates at a certain maximum frequency. The third generation of neural network models will use spiking neurons which encode information in spike trains.