How do I find out my iMac display panel's manufacturer? I've had problems with image retention on my late-2012 27" iMac for a few months now and Apple's "avoiding image retention" support page is useless for me.

On MacBooks, one can use this Terminal one-liner to check one's display manufacturer. Is there a similar command for iMacs? I realize that I'll have to return my iMac sooner or later because this is unacceptable, but I'd still like to know what panel I have before I do it.
It's an LG LM270WQ1 (SD)(F1).

One thread is here: https://discussions.apple.com/thread/5591164?tstart=0
And you can find replacement here: http://www.amazon.com/Apple-A1419-Screen-LM270WQ1-661-7169/dp/B00LEXN39W