Is basement waterproofing available in the old building from 1971?

Hello, if an old building from 1971 has dry walls, does it automatically have an intact waterproofing or is it possible that it has no waterproofing from the outside at all and is still dry? Can one also expect this to continue in the future? Recently, 50 liters per square meter rained and everything is still completely dry. Can I somehow tell from the outside if and how the basement is waterproofed? What should I look out for?

if there are no water stains, efflorescences, discolorations from inside or outside, everything must have always been dry. Has anything been newly painted or cleaned anywhere?

if there are no water stains, efflorescence, discoloration from inside or outside, everything must have always been dry. Has somewhere been newly painted or cleaned?

No, it is a basement that was lined with wallpaper and flooring, apparently still the first wallpaper and the first floor. So this should be an indication that I don't have to worry much about the basement in the future either, right?

Yes,
and a few more words

ok, What if the basement does get damp walls? It is a semi-detached house. The front area is accessible from the street by excavator, there is a garage on the side, and behind the house is the garden. Neither of these would be accessible by excavator. In that case, would only an interior waterproofing be possible and sufficient? The basement is only to be used as a utility cellar. Or could it simply be left damp? What would it cost and should one set aside the money?

Excavation can also be done without an excavator - it just takes longer. ;) I think in the 70s a basement sealing that seems normal from today's point of view could very well have been done. If you want to be sure, just check (with a shovel).