it is where they were stamped after jan 69. i cant say if it is orig or not. one thing to look at is the transmission stamp. it SHOULD look like the block stamp. but not always. you are asking about the 1 being bigger than the rest of the numbers right? they did have alot of diffeerent dies with different fonts. the stamp on my 70z has one character larger than the rest. if you are thinking of a purchase, have jerry inspect it first. too many fakes out there.