I think that the dates are encoded in a "least significant first" scheme, ie the year and month are encoded in the last digits, while the hours, minutes and seconds are encoded in the earlier parts of the digits.

However, I also have my doubts, because of these two lines:

1bd8 2a11 d97f e340   -->  01.05.09 18:48:05
1b64 9211 d97f e340   -->  01.05.09 18:48:05
[download]

For two identical dates the first six hex digits are completely different, making me wonder if they belong to the date encoding at all.

Are you sure that the binary data you show us actually encodes the full date?