Q: How should the date of birth field be completed?
A: For item 17 – Date of Birth:
a. (Check if) Unknown
Item *17 Date of birth: Enter the individual's date of birth in Item 17. Batch filers will use the format MMDDCCYY format where MM = month, DD = day, CC = century, and YY = year. The format MM/DD/CCYY must be used in Item 17 on the BSA E-Filing discrete FinCEN CTR. Any single digit month or day must be preceded by a zero. If the birth day and or month is unknown, enter “00” for the unknown day or month. For example, a date of birth with an unknown day in February 1978 would be entered as 02001978. Do not enter zeros for the year if the year is unknown. If the year of birth or the entire date of birth is unknown, check box 17 “Unknown” and leave Item 17 blank. If box 4 “If entity” is checked, Item 17 and box 17 “Unknown” must be blank.
This is addressed in the "FinCEN Currency Transaction Report Electronic Filing Requirements" guide, Attachment C.