Serial # and Paint 20k & 20C

[Hudson, NZ]

Does any one have access to definitive info re dates of manufacture. The early Cletrac data sources only list serial range ie 20k 101-10207 made between 1925 and 1932.

Is there anything more detailed that this? ie one of my 20K is serial K1414. Presumably this is either 1925 or 1926 tractor, but which? Has anyone researched when production started in 1925?

Colors: Am I right in thinking that CLetracs pre 1930 were painted grey with red tracks?

When in 1930 did the colour change to Brown occur?