A family of Microsoft word processing software products for creating web, email, and print documents.
All of those label numbers are available in the Word 2010 Label Options dialog. What may be confusing you is that the dialog's list is in "alphabetic" order and not in numeric order. That is, all the numbers, both four-digit and five-digit, that begin with '1' are listed first, followed by all the ones that begin with '2', and so on. Go to the end of the section that starts with '4' and then scroll down a few more clicks.
Also, you must select "Avery US Letter" in the Label Vendors dropdown to get the right list in the Product Number box.