The ad notes:
"This is for restoration use only and not intend for anyone to use to as a tool to make fakes. "
There are many people selling all sorts of replica WW2 militaria for the reenactor market, including ammo cartons, wooden crates, K-rations, etc. A few collectors will use such items in a display if they cannot get originals.
But, you can be sure that some buyer will take this sort of stuff and pass it off as the real original item. And, that someone will be gullible enough to buy it.
Gun collectors face the fraud problem created by the ready sale on auction sites of metal stamps to “restore” (i.e. fake) inspector cartouches on many types of firearms. Some are a bit off and can be detected easily, others are exact copies and almost impossible to detect. Caveat emptor!