User blog comment:Mckrongs/Monster Hunter 4 for the Nintendo 3DS/@comment-16218874-20130928172739/@comment-11685710-20130928184539

Those are the excavated armors ;)

That's just my thoughts now: I could imagine that 4's set in another time way ahead of MHFU and maybe even Tri...Those excavated sets are kinda like the ancient and rusted weapons: You find an old scrap of metal and give it to someone who's polishing it and making the armor for you. That'd explain the "modern" (3rd gen) and the "old/ancient" (1st/2nd gen) versions within the same game.

I don't know if they're better, but they've got random stats, sockets and iirc even skill points wich makes them similar to the charms in 3rd gen (wich are still around in MH$, too).