The article says “Activate the Paint Bucket tool after you click a material swatch (Mac OS X only).” so I would assume the same article is used regardless of OS.
Also secretly showing different articles do different users depending on OS would be quite stupid. There are all sorts of valid use cases for searching info on another machine, e.g. when you are helping a friend on a remote location or when you use your tablet besides your computer.
And ironically a lot of the imagery when setting it to Mac is from Windows.
If such an option should exist I think it should be a the top of the page next to SU version where people actually will find it. Even better, show and maintain the same article for all systems and if when differ, have a specially styled info box (e.g. yellowish background and the title “System differences”) explaining the differences. Even if you just use one system yourself it is good to know the differences to avoid misunderstandings with other users.