What brake pads do I buy in this situation?

So I feel pretty dumb asking this... but I bought my A4 from a guy who said he did an "A8 front brake upgrade". At that time I didn't really think about it but it's 9 months later and I'm changing the brake pads and realize I have no idea which to buy...



I realize I could just buy A8 brakes but I wanted to check with the smarter people here who might be able to shed better light on my stupidity...



I took the current set off if that helps, though I'll admit, it seems like an old set of dirty brake pads won't really reveal a whole lot.











Thanks guys!