You need to be able to revise/assign specification groups after publishing - this should be under the "edit details" for either the spec section or group. If you make a mistake and don't assign a group during publishing (since it is not a required field), there is currently no simple way to move that spec section into a group, and your specifications view will be incorrect and disordered. You currently have to delete the entire version set and reupload/publish. I believe this is a standard feature of Procore and other programs.