The Mannes and Godowsky Kodachrome patent of 1938 specifies CD-1 as the developing agent, the colour couplers they specified were:
cyan: 2-phenyl-phenol
yellow: acetoacetanilide
magenta: 1-phenyl-3-methyl-5-pyrazolone
these couplers produce poorer density when used with CD-3 or CD-4
The later K14 process used the newer couplers ( C-16 (cyan), M-38 (magenta) and Y-54 (yellow), and CD-4 for cyan, CD-6 for yellow and CD-3 for magenta (according tho the K14 processing manual)