GS1's document U.S. FDA Unique Device Identification (UDI) Rule Frequently Asked Questions address this in Section 4 (Standardized Date Format), question 4.3 as follows:
4.3 What if we don't specify the day in our expiration dates (or production dates)?
The U.S. FDA UDI Rule requires that a day be specified in dates. Consult with your regulatory compliance and quality teams to develop a strategy for specifying the day.
FDA guidance is found in the Unique Device Identifier System: Frequently Asked Questions, Vol. 1, question A.4. It appears FDA requires the specific day for all dates, except expiry dates
may use the end of the month.
[FONT="]A.4. Question: Is there a standard format for dates on the device label?[/FONT]
[FONT="]Whenever the label of a medical device includes a printed expiration date, date of manufacture, or any other date intended to be brought to the attention of the user of the device, the date must be presented in the following format: the year, using four digits; followed by the month, using two digits; followed by the day, using two digits; each separated by hyphens. For example, January 2, 2014, must be presented as 2014-01-02. See 21 CFR 801.18(b) for exceptions to this requirement. This requirement only applies to plain text dates on the device label. Dates in the AIDC technology portion of the UDI, or in the device history record, for example, are not subject to these date format requirements. In the event that a medical device expires in a particular month, but not a particular date, the labeler may choose the last day of the month for the date field because the date field is a requirement of the new format. [/FONT]
[FONT="]The standard date format is required for all medical devices unless excepted. This change should be implemented on the device label by the UDI compliance date for that device.
[FONT="]Given the foregoing, I don't think 00 will be accepted as va[FONT="]lid. [/FONT]I suggest you contact the FDA UDI Help Desk for a definitive answer to your situation. I can't imagine you're the only one who is in this position.