^^Trolling Findus???
Anyway, my mice looked like this straight out of the package:

On the left. a just opened mouse. I lightly scratched one pad on the bottom of the left one using my thumb nail. The one on the right is 2 months old. Notice how shiny the pads are.
In your pics you don't show or talk about gunk buildup. If there is indeed "gunk" then that points to use, but perhaps you are just saving face by providing such info now? In your pic I reposted above, it is very easy to see superficial scratches in new unused running pads. Probably those were made when packaging or unpackaging took place. They aren't really scratches but simply lines made in the residue layer coating the new rubber/plastic. Also notice how shinny the pads are on the 2 month old mouse. Even if only used for a day, they will become shiny. I have 2 more used mice and one unopened one so my little example can be repeated if need be.
Having bought 2 Logitech mice here I can attest to the fact that the pads on the bottom are marked out of the package and there are often scratch marks on the plastic on the bottom. I figure it happens at the factory and QC pulls these out form export shipments. You can see a couple scratches on the bottom of my Logitech mouse pictured above. They were there when I opened the package.The Logitech mice I bought in Canada were always spotless.