Wiper Arm Question

I don't know which, but one of them is not correct. They would not have come with two different makes and styles "I don't believe". Anything's possible, I guess. I always wonder though, how in the WORLD anyone can ever replace nice stainless blade holders with junk plastic? That was one of the first things I did to Vixen when I got her, was find the correct arms and blade holders. I THINK the Trico may be the correct one, but I am not 100%. Maybe some more smarter than me folks will know.
Dad's car was such a hodge podge of all different model years, just thrown together to make the car road worthy. So I'm sure one was replaced at some point. It's such a small part but just the look of the plastic wipers makes me cringe. Looks like a new car. Thats The last thing I want.