Hi,
I found this Curta on ebay. Below number 4 is number 7, see picture. Is this normal or could this Curta be rare? Have you ever seen anything like this on Curta?
Thanks



https://www.ebay.com/itm/166539828697?hash=item26c68c1dd9:g:We4AAOSw0Ohlmu4Z&amdata=enc%3AAQAIAAAAwEPKDt4IinYUVPJdV84nymQkxD7zTn0L%2B4ufDjwpabrKYO4ZepyZU9TCnlIHFgRPN9YqhsnPKoH4nOKwnCnJIqggke8YCcAnWlMc%2FGpvkZ0ETLeqcSAarxl21c%2FKhWHg4oZH58WXWS4sBA106ZqDyaxqZtRsK3AN0jCoW8UMrQummGFjlpzWAzkiKg%2BZIMCDf14gKV5Sg8JSWBcnPS4lQLk8qRt3ozWK%2F1MdeKacfSDlxbkU43H6gVYvtM6LgSAzVw%3D%3D%7Ctkp%3ABk9SR-7v3p2dYw