Nice looking G. I'm guessing there is a bigger tank in there, as the choke lever has been re-positioned to the hole normally used for the fuel shutoff valve to control the gas and all fuel tanks.
In the early 90's I saw one in NY state at a winter farm equipment show. The owner was not sure of its history, but knew it was unique. JR Hobbs, past writer for Green Magazine (now deceased), mentioned that 2 had been found.
I'm no expert, but I have never seen any info on the kit. Looks good though. Where is the tractor located?