Hey David,
Didn't you just get this great '83 bass? And are you already sure you can't get used to the pickup selector in its original position? If you're already bleeding from running into that sharp point, know that you can turn the actual knob around so that it points downward. (There are 2 set-screws in the knob).
If you are certain (already) that you need to move it, I'll mention a couple things.
First, the switch itself is able to be retracted through the body into the main electronics cavity without disconnecting any wires. Once you have unmounted the switch from the small circular brass mounting plate, you should be able to pull it backwards from the main cavity by gently tugging on the wires while helping it "turn the corner" with your other hand. The switch is prewired before installation so nobody has to do any soldering near the bass's beautiful finish.
Also worth noting is the "Keying" of the mounting hole - as you will see in the small brass plate - one side of the hole is flat, I think, like a D instead of a hole. (Might be two flat sides, I can't remember). But this p/u selector knob is probably the most used control on our instruments. It gets turned every time you plug in, unplug, in-between songs, etc.. It gets turned a LOT. That means the "key" is important to help keep that switch from coming loose and twisting at the most inopportune moment. So ... if you move this to be near the other controls, think about possibly a "keyed" back plate inside the cavity to help it maintain its resistance to rotate. I think the factory may do something like that when asked to locate the switch elsewhere but perhaps Mica can chime in on that subject.
As to what to do with the leftover hole, well, be creative as in that other thread mentioned above.
Think about it though... Give yourself a minute with the new axe before you make any big mods. Just sayin'.
Jimmy J