Hi all - I'm trying to buy a stainless barrel nut from Numrich, but their descriptions don't state whether the part is smooth or splined. Does anyone here have the details on which particular models have the smooth nut? I want the splined nut, you see... For example, they sell separate items for model 12FVSS and 16FCSS but don't give any details. I THINK the 12FVSS has a splined barrel nut (and the 16FCSS has smooth), but I'd like to be sure.

Thanks!