Here is what I can confirm so far, so if you are thinking about doing this - I did it for you:
I have a MacBook Pro 6,1 (i5 2.53GHz, 17"). I went ahead and bought 16GB of RAM, thinking it was going to work (unfortunately, I misread the website because I was so excited to see 16GB for MacBook Pro). Only the 7,1 model can do it and NOT the 6,1.
When I installed the RAM, the computer was able to "see" that I had 16GB. I ran into issues about a minute or so. Kernel Panic. Restarted the computer several times. No fix to this. I booted it up in Safe Mode and it lasted longer - performance suffered greatly, however. I tried to load a program and it restarted my computer again.
The pictures you see are indeed correct. What the ebay person did not tell you was that your computer will immediately go into kernel panic mode and restart.
I contacted Apple and they confirmed that while the computer will see 16GB of RAM, the moment it tries to access certain parts of the RAM (which happens a few moments after you log in), it crashes.
Not worth your time and Apple is not going to fix it - they would have already but they are making an OS that does not work/will no longer support old hardware. Saved you $80, hopefully.
EDIT: I tried booting up the computer with Linux and it crashed as well. The computer lasts long enough for a person to check the specs and display that it can handle 16GB. What really happens is that there are major performance issues. This is most likely a hardware issue.