This was my grandfather's watch, one that was given to him when he worked in Beira, Mozambique. I have seen one other Eterna with the EXACT same inscriptions on the inside back case, it was on WatchUSeek, with the same movement, though the case was different. Believe this is a Eterna cal. 165? Would that be correct? Was working relatively well until 5 years ago when it finally gave in, so it needs a tune up for sure. Can anyone date this? Cheers