Borges, or another writer, could have come up with this idea today
knowing how things were back when. Even if he/she hadn't lived through
it. I *think*

An affecting plot definitely could be carried out in a contemporary
context. An equally affecting plot? I don't know.

Perhaps there would be more technology involved. Perhaps a spy would
have to kill a potential friend and mentor in order to extract an
eyeball that would function as a key to a retinal-scanning lock on
something....Or. Perhaps they'd be in such a remote area of China, or
in such an info-jammed war scenario that the spy would have to resort
to this old-school method of using media to convey a message. But yes,
I think something could be created that worked...