Well, we can never fuss over our fish too much!
My husband knows better than to interrupt me when I'm talking to my fish, LOL
Clamped, scrunched fins do usually mean stress. The pics don't really look like what I would call clamped fins. I had a betta once that his tail hung straight down, and his top fin draped over his side. The top fin on your fish looks like it's in the right position. The tail doesn't look clamped either. Different bettas do have differently-shaped fins. One betta could have full and flowing fins, and another one could have smaller fins, and they could both be fine.
It wouldn't hurt to keep an eye on your betta to be sure. He may just be getting used to the tank changes that you made, and he'll be himself very soon. Is he still active and eating? If so, I'll bet he's fine!