While I thought these might indicate British Military Property, it turns out they are not the right sort of arrows for that. The Nazi's kept incredibly detailed records. MF markings have shown up on other Kriegsmarine Contax and Exakta 6x6 cameras. There is no doubt they were used by the W.W.II German Navy, but the exact means remains a mystery. With so many military collectors, it is strange to me this information has been so difficult to obtain.
Forgers wants quick easy money, something which can be sold easily.
It was apparently sold in Argentina, and then taken over in the Kriegsmarine. I expect the MF code to go a long way to solving this mystery, if it can ever be deciphered. If you have the answers to any of these mysteries, please please please email me. It represented the powerful Norse god Tyr. The Germans were fond of their presumed connections with the Nordic gods and used runes in many of their unit insignias.