Hi Alex,

I think it's units shipped by Apple after the release of the update that will have it on it. I don't see how units that were already out with distributors couldn't have the update magically beamed into them as it were. I think the salesman was being less than honest with you unfortunately. You could try contacting Apple and see if they will give you the update for free but I wouldn't count on it.

Sorry I don't have better news,

Bart.