This mark is found on modern-day reproductions (made in China after the year 2000). No matter what you are told, these goods are neither old nor rare. We know the true manufacturer and many of their business partners responsible for import and wholesale distribution. However, we are withholding their name in order to avoid advertising their business, and we will not discuss this matter further.
There is also an almost identical version with different initials; please see M180913.