Why Are There Twins On Some Of My Henckels Knives, And Singles On Others? Some Are Germans, Some Spaniards..?

I was really excited to receive this knife set for Xmas last year from a friend who has been my guinea pig for many a Sunday meal. I was watching Food TV one day, and the chef referenced the twins on the knives… I noticed one day that some of my knives only have one guy on them! I was with my friend when he bought this set at Costco, is it possible I’ve received a “defect” set *gasp* sold at a warehouse price for that reason?