Correct, but as one can’t prove a negative, we can’t say for sure how it got into the market. That being said, this phony paper is ludicrous.
The paper itself is full of howlers, in addition to being based on objectively false assumptions.
Here’s one of many examples:
Making such a large DNA sequence requires assembly of smaller DNA fragments to create the larger, full-length viral genome. Assembly of larger DNA sequences from smaller segments can be accomplished efficiently using restriction enzymes that cut outside the enzymes’ recognition sequence, cleaving fragments of DNA and leaving unique 3-4 nucleotide overhangs with unique sticky ends permitting reliable reassembly of the fragments of DNA in the correct order (Fig 1).
The authors haven’t looked into modern assembly methods. Either they haven’t heard of, or are concealing that they have heard of, Gibson assembly, which would leave no restriction-site fingerprints.
Even more telling, Gibson assembly has been used to assemble a MERS-CoV cDNA, but the authors conveniently didn’t cite that paper, falsifying their pretense of having performed a comprehensive search.