If it were mine, I'd feed it first. If it has sat for 30 years and the leather has lost all of its natural oils, it could split at the rivets the first time you ride it. Or, maybe not. I would put a liberal coating of Proofide or similar wax-based treatment on it, top and bottom, warm it in with a hair dryer, and repeat. Wipe off the excess once it's dry, and ride it.