Mike et al.
Somebody correct me if I am wrong, but I am reasonably sure that Sugino made models with the crank spider arms cut-out ala campy "mexico" cranks in the early to mid 70s. I only say this in that I recall the cut-out variety came on 1974 Fuji pro models.
To add more gist to the mill, I also recall Gipiemme made this variety as well. It came on a 82 Puch that my brother had back then. However, this may have been after Campy came out with their mexico model. Cheers,
Dave Anderson
Cut Bank MT