There were several models of Signal-stat units. My '53 has a model 700. It has only 5 wires and must use separate light units for the rear signals. (independent of the brake light units) On the model 700 the yellow wire connects to a two terminal flasher, with a fused hot wire to the other terminal. Then green to L front, red to R front, white to L rear, black to R rear.
Some of the other models can use the same lights for the rear and brake lights. (see the diagram Slow..Rider linked to)
Diagrams for a couple of models in the 900 series can be found
here .
I think
OldCarKook\'s website has a diagram for another model but I couldn't find it quickly and got lost in the other neat stuff while looking.
Hope this helps.