I don't think that there is anything fishy going on in the article; in fact, its findings fit pretty nicely with standard paleo views of fat. For starters, we know that fat, like carbohydrate and glutamate, produces food reward. That's why we love and crave our favorite fatty foods. These researchers are trying to locate the precise mechanisms that underly the process of coupling fat intake and food reward signalling, and it looks like they've done a fine job of locating one, using a pretty clever research design.
That said, as paleos we'd probably like to know if the gut responds differentially to different types of fat. Further, the study is done on rats, so its results might not generalize to humans. And the sham-feeding protocol sets up an artificial situation where the intake of fat is simulated, but not the ingestion of fat, which we can assume has its own unique affects on reward pathways. Finally, their research, like most, is geared toward producing an obesity drug that can affect these pathways. Obviously we paleos object to this because we know that dietary interventions are more effective, cheaper, and have no side effects. But there is no money to be made in studying dietary interventions, and hence fewer resources for researchers.
I must admit, though, that it would be pretty cool if obese non-paleos could take drugs that manipulate their food reward pathways and make them feel satiated more easily. We don't have to support the research in general and its motivation in order to recognize that :)