It isn't difficult to add the Spotlights. The backwire (red-grey) of both spots can be soldered on the left Martian eye (between the flipperfingers). The other wires will be soldered on the lamp pcb plug for the saucerlights/game modes. The left Spotlight (yellow-brown) has to be soldered on the same wire on the plug for Paris in Peril. The right Spotlight (yellow-red) goes on the center insert of the center saucerbeam.
The easiest way to find out which pins they are is to follow the lamp copper printig to the socket of the pcb.