Option for PRS-T1 driver to mark new books as read

This is an option for people like me who don't like the new books to be marked as new in Sony Reader as they use other ways of tracking their readlist.
I would like to expand this later in a full function accessible in other parts of calibre in order to be able able to manipulate the built-in collections without resorting to direct access by external plugins like 

BTW, if you have the time you may be able to explain a few things I find puzzling in python sqlite.
1-Is there a performance difference in cursor.execute and cursor.executemany? From PEP249, I expect the later to be better if many similar query are done.
2-Personnally, instead of using many queries, I would have done something directly in SQL if possible like a "WHERE x IN (list) " which is not trivial if you are not using execute with a string already including the list and not passed by the parameter. However, this is less safe from what I understand.
Am I missing something?