Hi There! If it says "made in Germany" you have a real honest to goodness German Petromax; however, if it says "Germany or German Regn or registered" you have a Chinese knockoff. Mind you, they can still be a good lantern but they are not up to a real Petromax made in Germany.
It's difficult to be sure from the photo, but it does appear to be a modern example. Is the owner asking much for it? The glass alone is worth about £15-£20, Jeff.
Yes that look the same as mine which is a modern one. I had it running once and it's never worked since.
That one's made in China for sure. They stopped making them in Germany in 1970 I believe. That one is obviously recently made by the looks of the nickel plating.
Last Petromax lanterns were made in Germany possibly as late as 1979, here is good information regarding the history http://homepage.ntlworld.com/munwai/petrox.htm that lantern, unless it has "made in Germany" on the fount and on the J tube holder assembly, is most likely made in China.