I'll readily admit to not being the biggest fan of colour matching everything on vintage racing machines, but in this particular case it actually works quite well. "Thoughtful execution" seems to be the key to success here. I like it.
WRT the frame's origin, I've been browsing back through this thread, and many things point it having come from Belgium:
- it was common practice in those days in Holland to import "blank frames" from Belgium
- the lack of a serial number was part of that concept
- the Belgians were early adopters in Europe of Japanese products, such as Shimano parts and Ishiwata tubing
- the look of the seat cluster, especially the seat stay tops, jibes with many other Belgian frames I've seen
- the mix-n-match approach was always popular in the low countries