Also, of course, missing or non-original parts can adversely affect value, in some cases even if the non-original parts restore or improve performance. That can present a dilemma when it comes to classic pieces such as these.Yes- back when the Japanese were scouring the country looking for equipment like this (1980s and 1990s), it was really important to them that the equipment was in original stock condition, despite that meaning that it was essentially unusable!
So a restoration should be done that makes it really hard to tell it happened.