If you are wanting screws for an old keyboard, or anything else apple for that matter, we more than likely will have options around the office that we could help sort out for you.
Just go to our website and drop us an email through the contact page and we'll let you know what options we have available.
Those old pro keyboards are quite a common, so we often have them around and use them for testing when we get large batches of machines in.
http://www.thebookyard.com/contact.php