IF you were going to make a new handle for it, I'd vote for a five-pin wooden scale handle, not an antler one. The five pin style preceded the three pin style. I think it would look pretty cheesy with an antler handle, honestly. Antler wasn't as common as folks often think, and when it shows up it is usually on an obviously one-off knife, usually rather crudely made. This, on the other hand, is a standard butcher pattern that was used from about 1800 on, and should have a "factory" type handle on it.
I vote to leave it "as is," for what it is worth. If you are looking for an "old timey" knife it already fits the description, and it you are trying to fit it to a particular period you'd be better off starting from scratch.
Any marks on it?