[Is this a 1958 Les Paul Special?]

I assume you can see some of the original color in the control cavity

 

Looks like that. a little tv yellow where cover screws on.

[Is this a 1958 Les Paul Special?]

58 was the only year that specials had that rubber ring. Mine never had it. Looks like a refin to me.

That was a factory color late in the production run, but then you would probably see a serial#.

There are also a very few documented 59 single cuts in that color, probably to use up left over bodies at the plant.

But you are most likely correct refined 58 special.

Pick guard was the same from 55-58 on the SC's, hard to tell but it should be B/W/B/ThickW/B if not it may be newer or a repo.

Newer Knobs.

[1963 Gibson Skylark GA-5T (HELP!!!)]

Put a grounded plug end on it. It is simple and may save your life. Beautiful amp by the way. Thought my Ga-8T was mint but that one is almost beyound mint.