On some shared hosting platforms, it is a security risk for the files to be owned by the web server user and not a FTP user.
See the tutorial on Changing File Permissions for more information, including how to configure file permissions so that multiple FTP users are able to edit the files.
You should always update Word Press to the latest version.
When a new version of Word Press is available you will receive an update message in your Word Press Admin Screens.
The The update API also support passing a partial document, which will be merged into the existing document (simple recursive merge, inner merging of objects, replacing core "keys/values" and arrays).
For example: In between the get and indexing phases of the update, it is possible that another process might have already updated the same document.
This means if there are any issues you can restore your website.
It is typical for the files to be owned by the FTP account that originally uploaded them.
(This feature was added in 2.7, so if you are using an older version, you will need to follow the steps to update manually.) You can launch the update by clicking the link in the new version banner (if it's there) or by going to the Dashboard Updates screen.