I am not at all an expert on Japanese coins, but I find both 50 mons rather doubtful. The 100 mon is assigned a date range of 1835-1870. It looks machine struck and it is copper. The guy behind lion coins didn't buy or sell it. He just saw it on eBay. NOT a recommendation. Yet, he assigns the same date range to the 50 mon, while that piece looks cast, rather than struck and grey metal (iron?), rather than copper. The wear on the lion coins piece suggests it was sloppily clamped and used as jewellery, which is highly unlikely for a base metal piece not offering a compelling graphic.
Peter