'67 Dart GT wiring question

Beware the 'OE' is now a marketing gimmick. There's at least one company that sells under the brand name OER, Original Equipment Replacement.
Real original parts will come in a box that says Chrysler Corp, MoPar or both.

It's even possible the replacement bulbs you got aren't actually the correct ones.
To reduce the number of different items in inventory, companies 'consolidate' part numbers if they can get away with it. So that's another thing to be aware of. Sometimes it doesn't matter, or at least to some people it doesn't matter and at other times it does.
A couple pictures here and some discussion
1034A (amber) LIGHT BULBS

and maybe you'll find the discussion here helpful in understanding the system.
Pulsating Alternator Gauge