Late 2009 but a different breed installing the iMac with a new HD .
The problem was a power surge damaged the drive and it just got worse in the end would not boot at all . Diskwarrior reported physical damage . That all happened in Australia and I was heading home to Bangkok and decided to give it a go nothing to lose .
The special tools arrived and I started the tear down as its called in the tech world . The tools did arrive on time and the tracking with Fedex is a great thing . With some dismay I saw "arrived" but couldn't find the address Bangkok is large . I have now updated my delivery address as I am keen to get some more gear soon . It took about 4 days to reach Thailand but another 4 days as the address had insufficient information .
There were some differences to the story but went ahead took the glass front off with the special suction cups its held on with magnets would you believe came off quite easily a little mac magic .
One of the differences that set the bells off was my Ram door had three screws and the one in the video had one .. Oh oh. Next the bezel on mine was not coming off but in a way that made it ok. No microphone cable to detach.
Next the LCD screen was removed and under that about  ribbon cables to unplug and there is the HD . Pulled it out and Apple my wife says “Oh we can get one at the Mall” ok lets go . 3000 baht later and back at the condo the fun begins .
Installed the HD replaced the screen and with some difficulty re hooking the cables to the best of my memory . They could really only go in one place due to the bends . OK all done left the glass and a few screws for now and inserted the disc and hit the power button.
Followed the instructions. Thanks for those the new HD had to be formatted for the Mac. Ok done . Now install seemed to be hanging took a long time but eventually happened . So happy with the result .
Have upgraded to Mavericks now and its working like a charm . I have a really good network here 10mbs download and unlimited access so I love Thailand all for $24 a month no contract and free wireless modem .
My advice is you can do it, just go slowly getting the first one done is a real confidence boost . I cannot tell how good I felt . And the inside of the iMac is not all that pretty [Steve] I have to say but all back together I am so happy thank you and love the stickers will be proudly sticking Ifixit on and telling the World .