New Idea built machines by batches or lots, so the lot number on the plate where the model number and serial number is will help determine what year is was built. Usually dealers have a book (sometimes repair manuals) that have this information. For example, I have a 701 Uni that is Lot#2, it was built in the first year of production, 1965. A person would have to know where the breaks are to determine how many lots were built in a calendar year.