Majority are green, but they are sometimes
gray. Tree frogs are arboreal, they like to be as high as possible and will "suction" themselves to the enclosure walls. As they age, gray tree frogs become bumpy in texture, but do not have single raised bumps (warts) like yours do. Perhaps an
identification guide can better convince you. Alternatively, a simple google search of "baby tree frog" versus "baby toad" will reveal yours doesn't share many similarities with the former.
Hoping you get your second opinion!