1970 E Body Broadcast Sheet Gurus

All you guys that collect 1970 E Body information, have you ever seen a broadcast sheet with a date the does not exist. What I am asking is a date such as on the 31st of a month that does not have a 31st in the month. Would it be possible to have: example B31 on a broadcast sheet or on a Fender Tag. Also have you ever seen a date that differs from the Fender Tag to the Broadcast Sheet on the same car such as the above example B31 on one and C01 on the other.

931 dates are common on fender tags & broadcast sheets for 1970 Hamtramck cars as one example. They are a great argument for the folks that think it is the actual 'build date'. It just did not happen that way.......