Frankly, it shouldn't matter if it is retrospective or not.
The only reason this would be a concern that needs noted is if people start trying to connect unrelated questions to each other. For example, I ask a question about a dog (without identifying the breed) and people assume it is a pug because in other questions I have made it clear that we have a 12-year old pug.
In my opinion, questions should be evaluated and judged based solely on the content of the questions and as long as the question is complete, on-topic, and is an (apparent) real world problem, it shouldn't matter whether it is a real actual question that the OP needs an answer too, or if it is a retrospective question, or if it is a completely made up question designed to help provide a solid foundation of questions on the site.
Now if the question is missing something, then ask in the comments if it is related to a dog mentioned in a specific question.