NOS NORS Definitions
NOS (New Old Stock) parts are Genuine Factory Original parts.
NORS (New Old Replacement Stock) parts are original vintage aftermarket parts.
NOS and NORS does not necessarily mean the parts are perfect.
Manufacturing technology was different from how it is today so imperfections should be expected.
Also, these parts may have been in storage for 40-100 years and could be dusty, greasy or have surface rust,, etc.