1) Presence of Helium: Obviously, if it is fusion, then there should be fusion byproducts.
2) Presence of Radiation: One of the big problems with believing the initial experiments is the fact that Pons and Fleischmann should have died from the neutron radiation generated. In D-D experiments, equivalent gamma radiation is expected to occur, although it would not be nearly as dangerous.
3) Variation according to concentration of Deuterium: How does the reaction rate vary according to the amount of D inserted? This should give important information regarding the reaction.
I assume that they have already tested for a different reaction given D as opposed to normal Hydrogen. It isn't explicitly stated in the article, but is highly implied from the context.
Even if the experiment turns out not to be cold fusion and is normal electrochemistry in disguise, explaining it should significantly improve our understanding of electrochemistry in certain contexts. Therefore, by making it duplicatable, at least some real science can come out of this whole mess. These scientists deserve reasonable praise even if it turns out not to be fusion.
They may have discovered something akin to cold fusion, but of a different nature. That is worthy of research and further investigations............
If this were in fact fusion we would have to keep fission reactors going just to produce heavy water.