For cars and trucks many systems needed "approval" or certification from the government as to operation. A vehicle when new would have been tested as to stopping range. However I am pretty sure none of the documentation would be available to a consumer from the manufacturer no matter what year of car and truck. Other than a sticker on all cars and trucks stating something like this ..... "This vehicle conforms to all standrads that were in effect at the time of manufacturing". A 46 year old car or truck may have that sticker and may not.
As to a travel trailer .......... not sure they have the same kind of standards as humans do not ride inside.
1966 Mercury Park Lane 4 DR Breezeway 410 4V, C-6, 2.80 - Streamless.
1966 Lincoln 4 door Convertible 462 4V 1971 Ford LTD Convertible 429 4V Phoenix ~ Yeah it's hot however it's a dry heat!