Some reading i did a while ago on US Jeep forums suggested that this slight change to the filters was specifically for the Dodge Ram versions of the same engine. The Rams apparently use a different filter housing mounted on a different angle and required a change to the smaller o-ring location to ensure sufficient oil pressure. There was a suggestion that GC's are not affected by the same issue so either filter will work fine.
In order to continue manufacturing just one filter for both versions of the engine, Mopar have changed the part number to the new one for both cars. On Mopar's site they now supply the later filter number as having replaced the earlier for all models. Presumably because they've stopped making the old one altogether now.
This could be worth further investigation for absolute clarity I think...
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