Not even close, he failed his other test:
"The Brazilian fighter tested positive for drostanolone, an anabolic steroid, in addition to a form of androstane, on Jan. 9. He tested positive for drostanolone again on Jan. 31, as well as anti-anxiety medication, which also is considered a banned substance."
http://www.espn.co.uk/mma/story/_/id/13432162/anderson-silva-suspended-one-year-failed-drug-tests
Also remember this:
"The Brazilian fighter tested positive for drostanolone, an anabolic steroid, in addition to a form of androstane, on Jan. 9. He tested positive for drostanolone again on Jan. 31, as well as anti-anxiety medication, which also is considered a banned substance."
http://www.espn.co.uk/mma/story/_/id/13432162/anderson-silva-suspended-one-year-failed-drug-tests
Also remember this: