Question about warranty booklet

Hello, this is my grandfather’s watch reference 145.006-66 (i read it on the caseback, i also have the gold bracelet but i changed it for an alligator strap).
I found this warranty booklet that i think belongs to it because as far as i know he didn’t have another omega chrono and the price is expensive at the time for a steel watch
But my question is that the reference number doesn’t match any omega watch because i tried searching for it on the internet.
I tried searching for the store and it seems legit so my question is it normal for vintage omega watches to not have the right numbers on warranty booklets?

Thank you for your reply, i’m thinking about servicing it so i’ll ask the watchmaker to tell me the serial number and i’ll check it.

Do you know what the metal field on the warranty means?
I tried looking for the number on the internet and couldn’t find anything