Ebony can vary from light brown to extremely dark, and the darker examples frequently do not show much, if any, grain pattern, especially if they've been finished well. Is there any spot where you can test the handle where it won't be seen, like under a cap or anything? If so, you can try a heated pin held in pliers to see if the substance melts, which would tell you that it's composite.

Growing up in Africa, the ebony fakes I saw were generally actual wood rather than composite, but had usually been heavily treated with shoe polish to get the look of ebony. Those you could test with alcohol and a rag, but it seems hard to tell if it's a composite or not, especially without damaging the material.