Norris-
I can comment about Singer being busy in the mid 70's, a friend ordered one in 1974 and was hoping for a 1976 delivery, but he wanted a lot of features to exploit their capabilities.
Beyond that comment, this auction is where the limits of lower resolution digital imagery and possible selective composition really hurt, the C.N.C's I have seen in these parts, although under a dozen in total, exhibited very nice workmanship and sometimes unfortunate paint. With one really standing out above the others, as it was allegedly a "show" bike. Knowing C.N.C. was a small builder, I always wondered if exhibiting made since for them, at a venue such as the Paris trade show for example.
The images of these bikes on auction are not good at assisting the case of fine craftsmanship, no matter who built them.
And the smaller black bike, has what one could call intriguing angles possibly, as well as a curious selection of rear dropouts.
Thanks for your efforts to shed some light on these.
John Jorgensen
Torrance Ca USA