Couchbase - Get document creation date

Is there a way we can get a document's creation date in Couchbase (2.2.0). We are currently not storing creation date in our documents, so wanted to know if couch stores that as part of document meta data. We plan to query documents based on time, and currently the only option that we think will work is to change the server code to store additional creation date field as part of the document itself.