Is it reasonable to think that Oswald made this bag out of paper and tape? It obviously has a flat bottom. So, how did Oswald make that? How did he learn how to make it? Most of us go our whole lives without ever once making a bag. So, how did Oswald know how to make a bag with a distinct bottom? Isn't that just a little bit too nifty for Oswald to have made it?
The fact is that that bag is so nifty, it has never been duplicated. When the FBI made a surrogate bag, it wasn't as nifty as this. It was crude, in comparison. I guess Oswald was a bag-making genius. We're all good at something.