303.02(b) "Mail Room Date" Label Showing Receipt
The USPTO places a bar code label indicating the date of receipt on every application, part of an application, amendment, letter, or other document submitted to the USPTO on paper. The label is referred to as the "Mail Room Date" label, and it establishes the date of receipt (i.e., the filing date) of any document. Before 1998, the USPTO used a stamp, known as the "Office Date Stamp," to indicate the date of receipt of incoming documents.