Car reassembly. Observation made on turn signals...is this normal?

The new paint is finally on and now I'm putting the '68 Dart back together. I installed the rear tail lights and checked the turn signals...got nothing. Although the bulbs were still good, i put in new ones to double check. No difference. Went through hours of going over the wiring, grounding, flasher, turn signal switch, etc.. No luck.
The fenders weren't on yet so I didn't have the grille in place. I decided to temporarily attach the grille and connect the wiring to check the fronts. They worked fine...checked the rears...now the rear signals are working fine.
So my question...Is it normal for disconnected front signal lamps to have that effect on the rears? I wouldn't thinks so, but i want to be sure that the wiring is correct.