Thumb Drive with deleted/overwritten files but UC is all 0's

"I'm analyzing the image of a thumb drive and have located 7 deleted/overwritten files,"

This is the most significant observation in my eyes, you must be explain why you state you can see deleted/overwritten files. I think you may be looking at a Recycle Bin anolomy and there is no evidence of wiping rather that the zeros have been there since the last format.