Reverse lights??????

OK My memory serves poorly as of late,,
67 in cabin reverse wires were a violet and violet with a white tracer ( that tracer was very difficult to see ). A dash mounted reverse indicator lamp would get only 1 of the wires being the switch activated hot. That indicator bulb would be chassis grounded. Now automatic.., same as above, hook up the 2 wires. isolate or delete that branch to indicator.