It indicates the one you can see is working. Doesn't confirm all around are working. Same as the one in the inst' panel. I'm more a fan of a noisy flasher module but todays stereos and ear buds would cancel that out. My 73 Valiant had signals on the hood but I honestly don't believe I ever looked at them. I'm always looking well ahead of the hood and quickly glancing at rear view and inst' panel/gauges. I know the signal flasher, cancel cam and all do work in the 2010 RAM I just bought but I haven't heard its flasher module sound.
Most are not aware of this bit of mopar trivia... When the earliest 1969 model Darts rolled off assembly line, the bean counters had decided they would save some coins by omitting the signal indicator bulbs in the dash. That's right, no change in inst' panel, 2 green lenses remained with no bulbs behind them. So many buyers complained that allma mopar could do was say DOH! and install the 2 bulbs in the panel and no charge. Within 90 days of production begin, those 2 bulbs were added back to panel assembly.
On a lighter note... I've got a copy of Mad Magazine that was issued same month my 67 fish was built. One segment is about cars of the future. A robotic hand would come out of the dash and slap the driver upside his head for reasons like "turn signal left on" or "Dozing off behind the wheel".
It would poke tobacco products in your mouth and light it also. If I recall correctly, the 3 button options were regular or menthol cigs', and cigar. LOL