OLE 1 and Gadgets both appeared in 1990; Marais references the 1989 InterViews (Linton, Vlissides, Calder) publication in his 1990 report. See also https://doi.org/10.1080/10618600.1996.10474712.
It is important and also helpful for the younger readers to name and correctly attribute the essential achievements. E.g. one fellow stated that "OLE was introduced in Windows 3.x", so it is important to note that the Oberon Gadget system appeared in the same year, and the component system was an independent achievement, that took a completely different approach than OLE or OpenDoc.