Normally, I would agree, but my Lucas one is weeping after less than a year :( Had the same problem with rear wheel cylinders.... fitted genuine Lucas and one failed at just over a year.
I doubt Lucas ones are actually 'genuine' any more. They fill the box with whatever is the cheapest option, as do AP Lockheed (Delphi). We are fully aware of this from the Classic Mini market. Many of the Lockheed boxed items are actually Italian imports.