If it has the same Broadcom 802.11ac chip/board, it could potentially have the same issue. However, it may have been fixed by the time the iMac production runs started or not. You may check the Apple Support forums, as I understand there is one Broadcom part# this is affected, and one that is not. This suggests it may be a board or firmware problem, and was fixable. However, if it's an issue in the silicon, there won't be a fix until the chip fault is fixed and a new production run occurs at the fab. This process can take 16 weeks or more. I would suggest waiting until the new iMacs come out, and read the reviews to see if the WiFi issue still exists by then.
The consumer really loses out in these type of issues. First, Broadcom hides the issue from Apple, then Apple finds out and will not acknowledge it while pushing Broadcom for a fix. If there's no firmware workaround, then Apple has to decide whether to come clean and eventually do a recall to replace the faulty hardware (board or chip). This often happens in adoption of a new standard such as 802.11ac, where the first version has several bugs.
I also returned a 2013 Air for this reason, and am just keeping my 2010 Air.