A complete text of Treasure Island on line.
http://www.bibliomania.com/Fiction/stevensn/island/index.html
The Question and Answer section for Treasure Island is a great resource to ask questions, find answers, and discuss the novel.
Silver is not the good guy... he is a bad guy. Note, the novel does not address how he got his name, but several sources infer that the name is a reference to his height.
From the text:
On the first page there were only some scraps of writing, such as a man with a pen in his hand might make for idleness or practice. One was the same as the tattoo mark, “Billy Bones his fancy”; then there was “Mr. W. Bones, mate,” “...
This includes a thematic component to your question. Certainly, the protagonist Jim Hawkins shows a sense of moral traits that is important to his character and the book. Jim is truthful, resilient, and sympathetic. Jim learns when to trust people...