Chinese official websites are not usually created with the user in mind. I would assume that 2013 refers to the year, and that is the one I would use. However, I have completed an application form before, and then had to complete an identical one when I arrived at the Visa Office. I think they left the old one online when they last updated it. Probably there is a 2008 version lurking somewhere on the website as well. If you are really concerned, pay extra and use an agent.
Re submitting on behalf of someone else, there is this: Important Reminders for Your Visa Application
2. Applicants should be physically in HK. Applicants may submit applications in person or entrust other individuals or travel agencies to do so. Applicants have to write an authorized letter enclosed with copies of photo IDs when they entrust other individuals or travel agencies to submit the applications.