Bill, first off a hand canon is a totally different animal from what you have in a million different ways.
Second, Mark's is real, the flash on it is to display wealth by the owner. My teppo has kamon engraved in it. My new rifle has a dragon carved in it.
You need to ask your self, who are you trying to convince this is real? You have 5 pages of people, some top experts, telling you it's not. So, you need to decide. I think you have sufficient information to decide. But trying to post information that tries to map your gun to authentic Japanese is not going to change a lot if any opinions. Even if the barrel is signed, the rest is not right, that does not make it what was advertised to you by the seller.