Does it have to be the whole dream makes logical sense for it to be a memory or can it just be partially a memory and partially gaps being filled by imagination?
From what I've read, this is unlikely.
Dreams are generally the clearing-house for thoughts/feelings/experiences you are consciously aware of. You may not be focusing much on them, but they are with you in your waking life, resonating off of other things, sometimes running in the background, or sometimes front and center. Things in dreams can associate off of each other in ways that are surprising to you, but not completely unknown to you (if that makes sense).
'Buried' memory is more likely to surface when you are in a conscious waking state and present to your environment. It's more likely to be prompted by something sensory - smell, taste, sound, touch, sight. External input, not the deliberate act of trying to remember.
The tricky part is - if you are wondering about your dreams during your waking hours? The wondering, and the things you are wondering about will - in fact - likely show up in your dreams. A little bit like the old brain-teaser, "don't think about pink elephants".
Recovered memory is dicey concept. Humans are capable of 'remembering' things we've never experienced - which makes it pretty easy to induce or create false memory.
It's fascinating stuff (even before you get into the deja vu phenomenon, and other ways our brains can trick us)...I'm absolutely not saying that you don't have memories that you've buried; simply that, they are extremely unlikely to emerge from dreams, but you could easily come to believe that your dreams are showing you memories - so, IMO, better to not spend a lot of time on it.
'Recovered' memory also isn't unique to traumatic experience, and I don't believe there's any science supporting the idea that traumatic memories are any different from other things that people forget. They are created differently - but stored the same as other forgotten (i.e. subconscious) things. If you've ever smelled something that you haven't smelled for awhile, and it immediately conjures up a set of associations - that's a 'recovered' memory.
I know I'm dropping a lot of info without providing citations....I should be able to share some links to this stuff later. Or, happy to be told that I'm wrong (it's been a few years since I was really deep into this stuff)