There's not enough info known to make much of a guess as to what was or was not done.
Does the engine idle smooth; and I'm talking glass smooth with no stumble, etc?
You might consider having a parts house like AutoZone scan your car for any codes. If something was not aligned properly during the belt change it's at least possible a code could be set. They will do this for you free and it only takes a few minutes.
Wished I could be precise on this but there is just no way of knowing. Even though your car is aged it only has 57k miles and the engine should be in as new condition with no noises or vibrations.
Wild guessing, I would say that it's at least possible that something is not aligned correctly; camshaft, balance shaft, etc.