Hey Mark,
not sure if this helps, but I have a 2014 CK30 and I wanted to replace the oil drain pan plugs (2), and found out that they were the same as my 2013 Toyota Tacoma v6 4x4.
Here is the link for the plugs from Gold Plug, although I can't be sure that my size will fit your tractor. Keep us posted, Dutchy Search Results kioti - Gold Plug LLC – Magnetic Drain Plugs