Outlook Web Access ID strings

Greetings

I have recovered a number of OWA records from unallocated space and noticed that many of these have very large "ID" strings consisting of HEX data.

I was wondering whether anyone had any information on the structure or content of these strings and, in particular, whether they contain date/time information?

I'm pretty sure that they don't contain Windows date/time information, at least as it is commonly represented in Windows, but they could be in some other format.

Thanks in advance.