Can shadowknights raise their throwing skill?
 

?

I can't answe your question, but your dig has me in tears right now.

No.

Unknown.
However, clerics do not have Throwing as a skill. YET, I have Bracer of Hammerfall that summons the only thrown item a cleric can use and gained 50 skill points of Throwing! Throwing still not listed on the skills pane.
But 50 points are there! Somewhere....