no this is not true, i fly a 20 - 30 year old Cessna 172, and its registration is VH- UOR, not a special registration as far as i know
That's actually quite funny
20-30 year old GA machines are not considered vintage, good man, we're talking about flying machines from the 40's or 50's like the venerable Tigermoth
A thirty year old airframe, properly maintained, will be of a technical standard comparable with a ten year old car.