A request for the benefit of the filing date of one or more earlier applications shall not be admissible where:
1° It is not made at the time of filing of the patent application;
2° The filing date of the earlier application or applications, the benefit of which is requested, is more than twelve months earlier;
3° The filing of the application or applications, the benefit of the filing date of which is requested, was made under conditions which do not allow publication thereof.