As I’ve mentioned on my Wikipedia profile, building numbers on the OCAD campus are almost always buried inside a system of 4-digit room numbers that is both bizarre and confusing (not only to visitors but also, at least sometimes, to students). So normally, unless you use your brain to do some inference (which is easy, but which Wikipedia for some reason abhors), you almost never see any “proof” that this system of building numbers actually exists.
However, sometimes the building numbers do surface on maps, such as on this map that I photographed during my second semester for reference for our installation project. As you can see, all numbered buildings on this map are actually identified by their own numbers, except for the Main Building, which is identified as buildings “A” (first to fourth floors) and “B” (fifth and sixth floors) instead of as building “0”.
Aside from this version of the campus map, I believe I have only seen standalone building numbers on a map in the 2012 student handbook. I believe I’ve also seen the system mentioned in passing in a style guide, but yes, that’s about it as far as I know.