Idler arm question for 68 dart

I don’t really know what the previous owner did so maybe he did tweak it including what suspension pieces he mixed match together. When I first looked into a part numbers I did check whether the part was the same for a six cylinder or big block and they both listed the same idler arm part number on rock auto. The stud on my idler arm points up .
Yeah I just saw the same at Rock Auto. this "one size fits all" isn't what I remember from printed paper catalogs back in the 80s. I'll question my memory. Good luck with it.