It can't have been. They didn't have Photoshop back then.
Photoshop was originally based on real world techniques. The first time I used photoshop in 1993 it really was just a digital version of the darkroom. I used dodge and burn a load, no layers and that but paths. The masking and editing that it has become famous for was in that too and it was damn cool. But it only copied what could be achieved with editing photos together and negative re-touching. Whether it was as good/seamless as it is today with photoshop I don't know but I dabbled in the 80's with prints and negatives in my teens adding a deceased member to a family portrait and it was pretty decent for someone with little experience. So maybe not photoshop but the potential to manipulate, quite convincingly I'll say, pictures can be manipulated.