My score is over 67 points in self-assessment. Can I understand that I will be issued a permanent resident visa?

Unfortunately, self-assessment can not promise you anything with regards to your application. More often than not your understanding on requirements can be wrong. Even if your understanding is correct, the supporting documents you prepare might be insufficient. In fact, in some cases, even if your score is high enough, your case could be still denied if immigration officers judge that you are inadequately capable of establishing your life in Canada.