with the focus on matching bikes.......in more recent times more a thing for the investors, actual riders probably don't fuss about it so much.......
I'm an actual rider but, for me, there's an indeterminable extra pleasure in having matching numbers bikes. I have quite a few motorcycles, all but one of which have matching numbers. However, there aren't enough words in use to cover all situations. Mine commonly would be called a "collection," but I've "acquired" all of them rather than "collected" any of them. A "collection" should have some theme that connects them (all models of Vincents; all models of BSA made a given year; one each from major British factories; etc.), and the only theme connecting mine is that I acquired them. I have a collection of motorcycle books, but an accumulation of motorcycles.Provenance is part of that but the extent of its importance varies between different enthusiasts.