I got mine Saturday as well. Just now had a chance to look at it.
Same Seller, same model number and the serial is G 001686 049, so late in the series like watduzhkstand4's. Pulled a few keycaps to see what was hiding underneath - appear to be MX Browns EXCEPT that last F key, which is also a Clear like his. Interesting.
Mine also came quite dirty, but in addition the right bracket key was askew, impinging on the Return key so they both went up and down together when either was pressed. Upon taking the cap off, the bracket key switch seems to be askew with the left side elevated up off the PCB, but not loose at all. Not a good sign. I will have to open up the case to see what's actually going on.
Haven't checked for electrical condition yet, but all this was a big downer right off the bat, except for the double-shots and the Browns, of course

Also, the touchpad's left-click button seems to be completely loose (in contrast to the right-click button, which is tight and firmly attached). Still feel the switch activating, it's just that the plastic button itself is really, really loose and floating in its cut-out.
Certainly not what the Seller claimed:
"This keyboard is in great shape. It is very clean and has minor wear. The keyboard has been tested and it works."
I'd say a great big FAIL on all counts since even if there aren't any electrical problems, the jammed Enter/Bracket keys would have made it pretty well non-functional if they'd actually tested it.
Oh well.