As a rule if you are caught in possession of any stolen materials at the minimum the items will be given back to the rightful owner. And you'll be out of luck unless you can sue the person who sold the item to you.

Innocent until proven guilty? Well if it's against the law just to possess stolen items and you are caught with them, you are likely to be found guilty.

I haven't heard of anyone convicted of such a crime; however, I do know of one case where a guy spent over $1000 for a nice bike and lost that money when the rightful owner saw him riding the bike.