A work in progress, of course.
A list of all the Capless models by Pilot:
1963 - C-600MW and variations
1964 - C-300SW and variations
1965 (I) - RW models
1965 (II) - C-500MW and variations
1968 - C-250SS
1971 - C-400BS and C-400SS
1973 - CN-400BS & CN-500BS
1984 - FCN-500R and variations 1998 - FC-15SR and variations
Notes on nib units and Capless models.