A friend of mine took a look under my truck and said my camber bolts are "totally out of wack". My truck drives straight (although its main concern is following any and all lines it finds), and my wheel is centered... but did I do something wrong?

 

Did he say anything about all the oil you're losing?

Your alignment discs are set mostly to one side. So what? They were probably more centered when your truck left the factory, but sometime in the past 25 years someone hit a curb, and now they're rotated a bit to set your alignment correctly. The only way to tell if your alignment discs are in the correct place is to have the alignment checked. You have to have a real sensitive touch to tell, just by feel, if they're off. (And if they are off, you'll have increased asymmetric tire wear, and it will affect the steering subtly.)

 

Looks like you might be adjusted to give a little bit of toe-out (rear sweep) on the control arms.

.. Mine aren't this symmetrical

 

I was an alignment tech for over 10 years, pay NO attention to what the bolt adjustment looks like. It means NOTHING.
If your tires are not wearing funny and it isn't pulling to one side you have nothing to worry about.
If you are worried at all first make sure all of your tire pressures are correct (some techs forget to check or are too lazy), no brakes dragging, and all of your bearings, steering/suspension joints are tight and go get an alignment.
Always, Always, Always, get a computerized printout of the numbers so if you have a problem you can post it here and we can pick it apart.
the adjuster bolts in your pictures are not just for camber, by adjusting them front/rear you also adjust you caster.

 

^^ eye balls and tape measure are just to get you to an alignment tech who has the tools to measure this stuff where half a degree makes a huge difference in the handling.


Caster has a HUGE effect on how light or heavy the steering is, that following grooves in the road feeling, and its return to center rate.