No magic, but I had a real weird situation that I have no way to explain. So when I wanted to upgrade using the airport utility which logically should pull 7.7.1 first and then later 7.7.3, neither would work. I restored to factory defaults in the mena time of this original posting, however pull down menu was not showing 7.7.1 rather it was still displaying 7.6.4, hence why I was so eager to get 7.7.3 binary and do manual upgrade. AS I found the code, before I went about manual process I went into my ~/Library/Applications Support/Apple/AirPort directory to check the version.xml file and voila it showed how I do have 7.7.1 running and installed way back , so then I proceeded the manual process I described above and it worked. You are correct definitely because 7.7.1 was already there, but to for me unknown reason it is not showing on the Airport Extreme and in the drop meny I explained/described, however definitely there and clearly reason I was able to do manual upgrade. In the light of my question and wasted exchanges with the previous poster I didn't describe this part because it was irrelevant as I was only asking how I can get the code. If I had time to deal with the bigger issue here I would ask Apple, ok why my utility was not pulling 7.7.1 or 7.7.3 and why I had to do all of this to finish simple process that should in reality happen in matter of minutes (I do not have check auto weekly for the code not do I like or trust that feature i.e. don't like auto upgrades...I like to see upgrades done, ppl use it, not report issues and then I do my upgrades). Hope this clarifies it further.
Editing /augmenting my response with a comment - I was even contemplating to complain to apple and reseller I got my device year + ago to possibly replace the unit, but now that it all worked out I am happy.
