Too old to register to verify the number below. Sounds like they are a matched set with those serial numbers on the hosels. To give you an idea of their value according to PGAvalueguide, which is the blue book for golf clubs: Resale Value $267.00 - $362.00

You can contact contact customer service at the following:

www.titleist.com/.../ask-a-question

Any club can be faked including serial numbers. If you are comfortable with your 710 AP1's I wouldn't worry about authenticity too much. They are way past warranty and any replacements will have to be done by hunting down replacements on the internet so just go out and enjoy them. When you get ready for new, just make sure they are fitted and purchased from an authorized Titleist dealer. Have fun out there.