Well, the manufacturer Josef Hack (RZM 7/103) is for sure rare and the manufacturer Carl Eickhorn (RZM 7/66) is for sure very common, but... In case of RZM daggers the rarity doesn't play a big role. I would definitely take the Eickhorn. Besides much better condition, it is a transitional model (with both factory log and RZM symbol), always more desired than late RZM model.