As far as I know there are no "kits" of decals in the Kubota parts world.
The following are suggestions as to how to get decals for Kubota tractors in general:
1) search on E-bay/Amazon by tractor model and keywords like "decals" - generally will get some decals for sale.
2) go to the Kubota website and then to parts and then to illustrated parts list
http://www.kubota.com/part/partsList.aspx
from there type in the model number and start looking through the manual for anything that looks like a nameplate or decal and write the part number down or use their online parts list generator and call you local dealer to order the parts. You can look by the part number on Messick's ot other websites to see if a picture of most/some of the decals and you can order/see prices there also.