I wonder if the reason Stepper's hooves are solid are because she is roan too? At any rate, her hooves are solid gray, yet she is without question a silver bay.
Yes, I think your lovely filly is a silver bay - here is a silver bay with a lighter tail and darker mane as a weanling - and as a yearling, it is the same.
Here are pics of my silver bay mare as a foal, she was so light she was registered as a palomino, but later testing prove she is silver bay (EE,Aa, no cream, no silver test available at time of testing):