Yes. Pretty much, my entire passability (what little there is,) is owed to HRT. Before starting HRT, my facial structure REALLY looked male. I had a huge-looking chin, a heavy brow, and my face seemed to pinch together when I smiled. I HATED it. Just over two months in, the muscularity of my face has greatly diminished. My skin texture has become much softer, the overall look became smoother and rounder, the muscularity greatly diminished, and for some reason my eyes started looking more open. Plus the loss of body hair, and how my arms and legs and chest actually look smooth now, instead of covered in speckled stubble all the time, has helped as well. Plus for some reason it has REALLY changed the shape of my legs. They look more conical now rather than boxy. And this is after only about 2.5 months of it.
I didn't dress as a girl EVER before HRT, so I don't really have a pre-HRT experience to go off of, but I have a sneaking suspicion that had I tried back then, I wouldn't have had a snowball's chance in hell of passing, while now I think I actually look half decent, although I admittedly do still have a LONG way to go.
Now, a big part of this is because I've been dieting like an absolute fiend, so losing 30 lbs in addition to the estrogenic goodies probably made my changes much more significant, but again, as everyone else has said, your mileage will vary. Having watched many Youtube "before and after" videos, there are SO many people who I would never have thought even had a chance of passing because of their bone structure, who shockingly not only passed after HRT, but looked downright gorgeous! So pretty much, nothing is set in stone. Some do indeed barely change, while others change so much that you can't even recognize them afterward.