Hello I am new to the site and very thankful for all the really goo info here. I happy to know there are other people out there who have the same questions I do. So I am trying to buy a zetor 4321 from my grandfather. It is one good machine as I have used it for a number I years. My problem is he doesn't remember what year the tractor is and I can't find any info on how to find out. I hear maybe in the serial number but am unsure how to uncode it. Any ideas? Thank you for your time