Fender Mounted Turn Signals

This was discussed on Moparts a year or so ago. The car being discussed was a 67 C-body I think. The dash lights were disabled when the light package was ordered.

My 68 Dart GT also has the fender lights. I am missing some of the bulb holders and just assumed they broke. It didn't occur to me until just now that they might have never been there.

What would happen if lights were installed in the dash? Would there be too much load on the flasher? Would the lights flash extremely fast?