In the U.S. I have not seen a spare tire in any, but the mark on the rug does look like a tire was sitting there.
I noticed by the Velcro on the bracket, it says "n Ge" which might be "Made in Germany". That might imply some part from the factory, although it would be strange for the words to be cut off, like it was adapted from something else. And the Velcro isn't enough to hold a tire in place.
Is the bracket plastic or metal ? Plastic would seem weak for supporting a tire, but the way it's shaped I assume that's plastic. Does the area around the Velcro look like that was cut out by hand ? It looks like the Velcro goes down underneath the bracket also.
Interesting find.