No, they were not probably just possibly.
Still, doubts remained because scientists had never been able to find a ribozyme that could synthesize the nucleotide building blocks from simpler precursors. Although scientists could propose ways by which the four RNA bases (adenine, cytosine, guanine and uracil) and the ribose-phosphate sugars could have arisen spontaneously on the early Earth, these prebiotic reactions do not seem to be sufficient for linking the base to the sugar phosphate--the critical step to making nucleotides.
In this study, Whitehead scientists took the approach of making 1,000 trillion random RNA molecules go through test-tube evolution to find those that could catalyze nucleotide formation. They found three different families of ribozymes that synthesize a nucleotide by linking the base to a sugar phosphate--a reaction similar to those used by proteins in contemporary metabolism.
"These ribozymes make only one nucleotide, and that is not enough. But the fact that they can do this is encouraging, and we plan to try further evolution to see if we can make them better and more efficient," Professor Bartel said.
the fact that the Whitehead chaps haven't produced an RNA replicator in a test tube yet does not really chip away at the notion of a pre-biotic RNA world. If they did succeed, that does not mean it happened that way. It'll be interesting to say the least when one of those guys produces a self-replicating form of RNA though...