I just stooped and took a look at my neighbors 1365. The serial number plate on his is located directly under the steering wheel, same as my 55. good luck. The 1255/1355 4WD was an interesting experiment with the concept of the small utility 4WD tractor. A very flawed experiment, but a worthy effort none-the-less. The 1265/1365 4WD was a vastly improved unit because of the knowledge gained from the 55 series. The strongest point of either model was that Fiat motor. The thing is downright miserly with fuel (would have made Jack Benny proud!) and the motor seems to go about a gazillion hours between overhauls. The 55 we have was bought in 1967 and is still on the original motor. The hour meter shows nearly 4,000 hours and the thing hasn't worked for twenty years, so i have no idea how many hours is on it, but there,s a lot as it was my fathers primary work tractor right up to his retirement about five years ago.