Where the first two digits are the year of release, the second two are the week number. Videocards issued before this date are not LHR.
The serial number is on the box with the video card."
https://bitcointalksearch.org/topic/m.57557716
https://miningclub.info/threads/kak-otlichit-lhr-kartu-ot-ne-lhr-gajd.85879/
well, i can assure u my gigabyte does 100 MH.sec with ETH (pretty much a FHR card), its a REV 2.0 and first 4 digits of the SC are: 2129
here is a pic from the BOX !
http://grabilla.com/0bb1c-323d2a77-3e14-4168-a74a-a3772e5b6ce5.png
mining:
http://grabilla.com/0bb1c-c536f644-f780-4151-9db4-5a004b40dd41.png
The cost of the same video cards is now 4200-4500 dollars per piece.