Make "Printable" button missing from model Edit page in 3D Warehouse

I uploaded a SkUp file of a small solid component that had been deemed error-free by Solid Inspector2, into the 3D Warehouse, marked “Public”. On Edit page, there is no button to mark “Printable”, so no *.STL file was made. (Later, I did export the SkUp file and saved as .STL.) Are the instructions in “Printables Feature - 3D Warehouse”, “Making an Existing 3D model Printable” inaccurate or was it my error in model or uploading? Thanks.
LocksetPart011.skp (239.2 KB)