This is for sure a very special and beautiful combination. I believe box can easily be dressed down and then looks very effortless and cool.
For me, the bigger question would be: what is your intended use for the K? Box is delicate with rain, it can cause blisters which cannot be fixed in the spa. Hence for me, it would never be a ride-or-die. If you are fine with using it only when you are sure there is no rain, go for it. If you find the lack of versatility difficult, I would politely decline and tell your SA. I am a firm believer in waiting for what you want. I have never felt that being honest with my SA worked to my disadvantage. A few weeks or months later, I usually got another offer. HTH, good lock with your decision!