Happy to help.
Only Special Sedans and Special Station Sedans came factory fitted with indicators. Utes, vans and 'Standard' passenger vehicles had no blinkers.
Obviously blinkers were routinely fitted after-market. There were strap-on style kits that were carried over from 48-FJ models (none of which had blinkers), that fitted around the steering column. There was also a NASCO blinker kit that had all the globes and other bits and pieces required to add blinkers to a standard vehicle. The wiring loom that runs through the body of the car included connections for this - you didn't have to run additional wiring to install these. There is a blanking plate where the blinker stalk fits on original standard vehicles, but this could be replaced with the complete steering column blinker assembly from a Special.
All FEs and most FCs that had factory or NASCO indicators had flashing brake-lights, and the clear lens at the bottom of the tail-light assembly was only used for reversing lights where fitted. (Reversing lights were an accessory, not fitted as standard equipment on any FE/FC, but like the indicators, the necessary wiring was part of the loom.)
FCs manufactured in the last few months of 1959 had amber indicators separated from the brake-lights into the lower part of the tail-light assembly.
There's a bit more info on this topic in the Tech Info section. You'll also find an excellent diagram in the Electrical section of the Workshop Manual that shows how the blinker can connects to the brake and indicators to make this entire arrangement work. Also, towards the bottom of the
Tech Info index page, you'll see links to some Wiring Diagrams that might be quite useful when working on this.
Hope all that's helpful.