It's exactly like that. Animations are based in keyframes. If something is completely designed for low FPS, you naturally have less keyframes to work with. Blow the FPS up, and you can end up with animations that feel less natural and more synthetic because of keyframe interpolation.
Depending on how something is keyframed, the difference can be obvious or not noticeable at all. Physics can be used to make the difference less pronounced.
I'm betting interpolation is doing all the work. If they needed to add extra animation to make it look natural, I don't think they'd do it, as that would be a ton of work considering the amount of animations in the game. Besides, there's plenty of games which targeted 30fps but could do 60fps and beyond on PC and still have natural animations.