Another thing to consider is Admiral Motti. If A New Hope, he obviously doesn't have much belief in the force or the Jedi/Sith ways otherwise he wouldn't have been stupid enough to talk shit to Vader. You would think that a high ranking official would know well enough not to screw with a force user unless of course their deeds had faded into the obscurity of history. Even though it's only been 20 years, the original Star Wars does imply that the Jedi have been mostly forgotten so the likely hood that one specific Jedi would be a common house hold name at this point is highly unlikely.