Was I sold the right MacBook Air?

Ooops.

Once the new model comes out, it doesn't mean they immediately stop selling the old one. Have you correlated your 5-digit model# stamped on the back of the case for a precise identification of your machine?

 

Post what shows under 'About this Mac'

 

About my Mac - More info, it states there what model it is, no need to post anything, just look it up.

e.g. mine says:
Mac mini Server
mid 2011

 

Yes it does. The day the new units arrive in the store they no longer sell the older models unless the "business" teams are running some kind of special discount. The online store is also updated to reflect only the new models. I've never witnessed a case otherwise and I'm almost always at the store day 1 to pick up a new model.

There was obviously a mistake here. The OP also said he purchased in August, which I believe was several months after release of the update for 2013.

 

take it back to exchange for the current model that you thought you were purchasing.
advise Apple Customer Service by phone so that there's a record of your 'complaint'.

let us know how you fare …

 

Or it could be something as simple as the "Maverick Battery Problem."

 

Exactly what I was going to say. Do you have a 1.3GHz i5? It's a 2013. If it gets bad battery life, revert to Mountain Lion via Internet Recovery. Its basically the only option. I'll bet you find that your battery life throws down.

 

This would not happen at a apple store. however if you bought the laptop somewhere other then apple its entirely possible you could get a older model if they were vague when listing it.

 

a) where did you buy it from,
b) post what is in your "About This Mac" under the Apple Menu,
& c) make sure you aren't one of the 2013 MBA's afflicted by the Mavericks battery issues.