No, I'm not sure. The only real way to be sure, would be to visit a specialist who, after inspecting the area, could tell you whether there was any miniaturisation. All I can do is give you an objective opinion.
I can tell you that I have read a lot of stories from people who say that their hair has "always been a bit thinner in the temples", or that "one side was always weaker", etc (I also convinced myself for a long time!) but more often than not, there is early signs of hairloss. Your hair is still excellent; great density and (perhaps) only minor thinning on one side. finasteride/minoxidil alone could potentially fix this back to its formal glory - if there was hairloss.
If I was you, I'd either 1) visit a specialist and seek their opinion, 2) take a close up picture, in good lighting, with the hair fully scrapped back - then take comparative pictures, on a monthly basis. In the meantime, research the big 3, should you want to start this down the line.