This is a question I have been getting a lot recently. The short answer is yes, sociopaths are generally aware that they are sociopaths. This is one of the differences between sociopaths and narcissists. Sociopaths know they are different from other people, but can force themselves to think and act like a neurotypical person. Narcissists think they think and feel the same as other people (just better) and are consequently less able to alter their behavior, even if it would be in their best interest -- just another reason why sociopaths are better than narcissists.
The longer answer is that it may take a while for sociopaths to learn that everyone else is not like them. Most young children have sociopathic-esque tendencies: self-centeredness, lack of empathy, lack of consideration for others, dominant primal emotions, etc. It may not be immediately obvious to sociopathic youngsters when and if their peers have progressed past these "limitations" on their way to emotional maturity.
Meanwhile, the sociopath is undergoing his own changes. The sociopath is gaining a greater understanding of self. High functioning sociopaths learn that not only can they manipulate others, they can also manipulate themselves. This self manipulation can perform the same function as self control.
After the sociopath acquires greater self knowledge and self mastery, he may still be unaware that he is different. Instead, he may assume that other humans have just completed their own similar transformation. When the sociopath learns that he is the only one like him, it can be disappointing. It can be exhilarating too, but it will always be lonely. Not like most sociopaths mind (at least most of the time).