I agree that there’s probably not much value in just retreading the old specs, but I’d argue that just having the knowledge that it has been achieved in practice still puts you ahead of the engineers in 1961, and that the intervening decades of progress put you even further ahead.

There’s no reason to think that an equally well funded greenfield effort couldn’t land on the moon from a standing start within a decade; it’s not like we’re living in the shadow of an ancient advanced civilisation with no present day industrial capacity.