Normal temp gauge on my 69 Bee Rallye dash, no idiot light. However, I prefer to have a more accurate aftermarket gauge, but also like operating dash gauges since they're there. Same with aftermarket oil pressure gauge.
440beep - so from your last pic you are showing fittings in both w/p holes - Small one goes to idiot light? Big one with AN fittings to aftermarket temp gauge? Do you NOT have factory temp gauge?
short stack