The wire color is irrelevant if the wiring has ever been modified or re-done. Which is a good possibility on a 60+ year old machine. But here is what I can tell you....and it helps to have an ohm meter....
Whichever post is connected with the battery cable (here is where the ohm meter is handy) gets the wire that goes through amp guage and on to the key.
The other one gets the wire comming from the starter button. According to the print I am looking at, wire to the amp guage should be yellow, and the wire to the starter button shoud be red with a blue tracer
As to the screws, try as soundguy suggested, but I have found that it helps to be applying a little twisting(loosening) pressure when you whack it with the hammer. Not sure if that is what he meant or not.
And if you are looking for an excuse to get a new tool, this would be a good time to look at an impact screwdriver. They sure are handy:thumbsup: