Hopefully, someone official will provide you with an answer. But in the meantime... I would be surprised if that is an issue. I have created cards with digital designs that did not include any stamping (sentiment, background design, etc.) and have not received word that they are not accepted here. I also see cards where designs are cut from pattered paper and don't believe there is an issue with that either.
Looking forward to the "official" answer. I'm a rule follower ...