to somehow get the Leggings from the Scorpion set?

I read you had to buy them from some refugee @ Sentinel Island. Problem is, I'm already lvl 26 and roaming about in Orobas Fjords, meaning I can't go back there.

Is there a way to still get it?

There is no alternate way in the game to get the scorpion leggings if you miss them at the trader who had them.

It might me possible to get the leggings using the Activated developer console (though it has only been tested with the demo).