What is a real one?  

Dentman
Charles Eames designed the model 670 lounge chair for the Herman Miller furniture company. Your Selig chair was inspired by -- some would say "a knockoff of" -- that chair; Charles Eames did not design it.
Chairs like yours show up on Ebay fairly often, usually priced at a few hundred dollars. Here's one:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=110477239782

Fastfwd
Thanks for clearing that up. I looked a the link you sent (thanks) and found another one on ebay that more closely resembles the one I have. The only difference I can detect is that mine has the screws visible. The arms on this one are more like mine.
http://cgi.ebay.com/eames-lounge-chair-and-ottoman-herman-miller-rosewoo...

Differences
The chair in your Ebay link is a Herman Miller. Common, easy-to-spot differences between it and most replicas:
1. The screws holding the arms to the shell. As far as I know, all the replicas have those screws, even though HM's patent on the shockmounts ran out years ago.
2. The base. Replica bases often look VERY different from the HM base, with a different number/shape/finish of the spokes, different feet and glides, swivel/tilt rather than just swivel, or a square-plate attachment to the seat/ottoman.
3. The back supports. Replicas often have a different finish, shape, material, or attachment method.
4. Overall dimensions. Hard to spot at a glance unless you're very familiar with the HM chairs, but the replicas are often larger or taller than HM.
5. Arm upholstery. Most replicas have simpler upholstery on the arms than HM.
6. Big round holes on the underside of the wooden seat or ottoman. HM chairs don't have those holes.
The link below is to a random Ebay auction that happens to have really good photos of a replica chair. If you compare them to the photos in the auction you posted, and then to your chair, I bet you'll start to see more differences than just the arm screws.
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=140333973111

these are all selig and...
these are all selig and plycraft. both companies manufactured in MA, which is why that's where they're most commonly found.
prices can run from $100 for a beater to $1500 for a rare built in recliner chair (plycraft made them and possibly selig as well)
http://1.bp.blogspot.com/_YBAthzRXgUo/SBouHUp_L0I/AAAAAAAAAQE/qIk3beXXOL...