I checked the undeliverable list, neither Beastmen Seals, Kindred Seals, Kindred Crests or High Kindred Crests are listed there which might be an oversight on SE's part. As far as I am aware, it has never been an option to send them from mules to main or anyone else, and I can see why. There are always those players that would sell them. The only thing with the new update is that you can now store KC's and HKC's with Shami.