There are a couple of reasons why it my not have decals. First, it could be a warranty replacement frame. They often came with decals, so that theryey could be offered for multiple models, without the customer complaining that it wasn't the same model. .Second, some owners, particularly licensed racers, often removed decals (and even head badges) if they had an inferiority complex about riding what could be perceived as a lower status brand.


Here's a link to the decal set for the brand logo and model name as used on the early 1970s Nishiki Professionals.
https://www.velocals.com/search.php?..._query=Nish116