1970 Brake warning light on dash question -

The red light on the standard dash will light up when the car is started and go out quickly which is normal but should it also come on when I press the parking brake to the floor? It does not come on when I do this and was wondering how to fix it or if it is supposed to - I know it is also supposed to warn of dual brake master cylinder failure too but I dont have this problem so no way to tell if that is working or not or is there?

Thanks guys - after I posted this yesterday I went to the garage and poked around some more - I checked the owners manual and indeed the parking brake is not supposed to light the square in dash standard light but there is a rare option for a dime sized round brake warning light under the wiper switch and lighter that is supposed to do that - I went under the dash and found that I have no switch or wiring to the parking brake for that option. I also tested my brake pressure distribution switch by removing the plug and probing one prong at a time to ground with the ignition in the run position and found the brake warning light did come on indicating a properly working switch, wires and system. Seems as if all is well - it just has been so long since I have driven a 70 mustang on a regular basis that I had forgotten as I do not use the parking brake usually and when I did I was puzzled.