Apple released Wi-Fi Update 1.0 for late 2012 Macs on Monday. The update addressed connection issues when using the 5GHz band on new iMac, Mac mini, and MacBook Pro models.
New update addressed Wi-Fi issues for late 2012 Macs
The slim release notes included with the update state,
This update is recommended for all late 2012 Mac systems. This update improves compatibility when using the 5GHz band in Wi-Fi. Boot ROM or SMC Version Information: To confirm the update has been applied, the CFBundleVersion string of the AirPortBrcm4311.kext will need to be checked.
For those that keep track of their Airport driver version, it's AirPortBrcm4331.kext CFBundleVersion 612.20.15.
Mac Wi-Fi Update 1.0 is free and requires OS X 10.8.2 running on a late 2012 Mac. It's available via Software Update or as a downloadable installer at the Apple Support website.