Difference in side mirror arms?

[dmw319]

Is there a difference in the side mirror arms, according to what style mirror you have? I currently have the boxy side mirrors, but wanting to get the round mirrors and want to know if I can re-use the same arms and change ONLY the mirror.

I do realize the bracket connection to the doors might be different, but if I can reuse my arms I wouldnt have to worry about that part. I want to know specifically if the shape/size of the arms are different.

My truck (style that I have) :
http://savedalone.files.wordpress.co...7986417820.jpg

Square 78's tryck (Style that I want) :
http://67-72chevytrucks.com/vboard/a...1&d=1353503912