Amazon/macmall delay after launch?

Hey guys, I've just sold my main machine and am using a temporary old machine until haswell drops and the air is refreshed.

I'm wondering, how long after launch do the third party retailers get the updates?

The difference between paying shipping and tax from apple and not paying shipping and tax from say amazon is pretty substantial in my eyes on a ~1200 dollar machine (what I intend to spec out around)

Thanks!