That's not replication, that's polymerization. There's nothing template-directed about it, and as far as I can tell the experiment depends on pure initial conditions (the guanosine monophosphate is not mixed with a plethora of other chemicals that could copolymerize with it.)

That purity is the kind of artificiality I was talking about. A bad habit of OoL research is to show that some chemical shows up in trace amounts, then starting the next stage of experiments with a pure batch of that chemical. Robert Shapiro in his 1986 book "Origins" had some very biting things to say about this (the book is not nice to creationists either, btw.)