You can tell by the style of clamps. Take some close-up pics of the clamps for both the inner and outer joints and I'll be able to tell you. I mainly need to see the area where the band comes together.
I assumed you were talking about the front CV axles.
Anyone have any other ways to tell? I'm needed to know the same thing. There are supposed to be different style clamps for the inner and outer boots, yes? Mine have the bend over clamps on both.