My brother gave me his mustang which he never uses, and the first thing I did was open it up to tighten the volume and tone pot and to fix one of the slide switches. But there were two things that were strange to me.
First, the tremolo bar didn't move much, so I took out the tailpiece to check it out and found two wood pieces holding the tremolo bars in place.

I guess maybe this would be good to keep the guitar from going out of tune, but the tremolo is basically not functional. I'm think of buying the springs that are supposed to go there. (Hardware store? or Music Store?)
Secondly,
It had some strange hot rail pickups, which I don't really like the sound of. But two of the cables coming out of each rail pickup (red and white) were bound and set aside.

Are these cables supposed to be attached to the switches to be able to manipulate the humbucker functionality? If I do use single coil size humbuckers, could I wire it to use the switches for adjusting humbucker functions, like series or parallel?