Real chocolate can kill dogs, yes. It has to be the good stuff, with a high cocoa content. A Smarties Easter egg is probably quite safe - although I wouldn't risk it. Pukka Belgian chocolate - keep it locked away safely.
The one about raisins is a new one on me. According to the posts yesterday, there's a mould which can grow on grapes and raisins, which is poisonous to dogs. It's not the raisins per se. But I'd never heard about it till yesterday so on this one I am definitely not an expert.