My EXNH had an unbelievable memory. He could remember details and dates like no one I had seen before. However, there was only one reason why he remembered these dates and that was to garner Narcissistic Supply.
It's a great question, Aceone Lady. Whether their memory is different than ours. The answer is yes. Studies tell us we have two different memories for the same situation. One is explicit memory - a memory of the details of the experience and the other is Implicit memory - a memory of the emotions connected to the experience. For example, smelling a baked apple pie reminds me of my Grandma and brings about an emotional response of missing her. That is implicit memory. Explicit memory would be my ability to remember how to make the pie. - the details of the experience.
Narcissists are very good at Explicit memory - the details, the how to, when, where, what, etc. However, they have horrible Implicit memory, which is always triggered by an emotion, or sense of smell, touch, taste, etc. They are incapable of bringing forth emotional memories, only factual memories. They are incapable of emotion. Therefore, when you ask if they have memories about us, the answer is yes and no.
Yes, they remember the details (Explicit Memory). However, the emotions (Implicit Memory) are totally lost on them. They didn't experience emotions when it happened and certainly will not experience emotions when remembering it.
It's hard to accept, but it's simply the way they are built. Their ability to delete their memories about us, as you put it, is the only way they know how to survive. It's no way to live. Trust me, we are fortunate that we can feel. xoxo