two routers connected with serial interfaces and the first nat 192.168.12.0 into 10.2.150.0 and forword packets to the second one. Is there any reason to be present any entry for the network 192.168.12.0 at the static routes on the second router ?
No. The second router need not know how to route to 192.168.12.0 at all as that would defeat the purpose of NAT. However, the second router needs to know how to route to the NATted network 10.2.150.0.