Yep - I think I might have posted about this upthread (though maybe it was in the recent lewpuls alignment thread).
Gygax, in his definition of good, is completely casual across different notions of the good, including utilitarianism as you say, human rights (which is what he mentions in his stand-alone definition of good in his DMG, though to a Benthamite those are nonsense on stilts), truth and beauty (in his PHB), etc.
That's one reason why I think debates about whether good characters can be utilitarian or not is hopeless - alignment does not resolve moral philsophical debates but straddles them by brining all the standard views into the definition of good. For a paladin, I think it then makes sense to go to the archetype, the "code" etc. In 5e the Oath of Devotion looks pretty non-utilitarian and standard duty/honour to me.