I had read elsewhere the trackconfig was different but couldn’t remember in what way.
He stats on the 24 seconds mark that this layout if shorter, but the pinned comment under the video states:
Bellof's record was set on the same 12.9 mile layout of the Nordschleife we have in AC. The old 1982 layout included a 1.3 mile hairpin loop hanging off the southernmost point at the point where the GP circuit bypass is now (in front of the T13 grandstands). In 1983, the bypass was added, because construction was underway on the GP Strecke circuit, making the old hairpin loop unusable.Take your pick