If you can't tie the bills to Oswald or even the assassination, then you can't use them as evidence.
Here's a list of the possessions taken from Oswald after his arrest. Nothing about any torn bills.
There is another claim that the torn bills were found in his room at the rooming house. But I've never seen that documented anywhere. Doesn't mean, of course, there weren't any just that I've never seen it sourced.