We don't have any kind of validation at our side for the duplicate check. Every request coming to us is considered as a unique request and will be counted separately. The duplicate checks come up after the parsing process and RChilli is only responsible for JSON output. We don’t have any duplicate validation check at RChilli's end.
Also, you can start storing MD5 for files in the database. It will help you in identifying duplicate files.
Following are the few links that can be useful to you: