[Igofastr]

Sometimes the owner will supply the results of these tests.

On a Porsche forum that I frequent, this is commonplace. In fact, without them (or recent documantation of a rebuild), engins are often valued as a "core" regardless of whatever other stories the seller may be telling. Can they be faked, sure. But you'd have to have steel cajones to do that, and think you could pull it off.