Not likely. Golfer's elbow mainly causes pain on the inside bump of the elbow, the medial epicondyle. In severe cases, the pain may spread into the forearm. The fact that you feel numbness in your hand suggests there is more going on than golfer's elbow. Given the location of the ulnar nerve behind the medial epicondyle, along with your long history of golfer's elbow, your symptoms may be from a condition called cubital tunnel syndrome.
An early sign of cubital tunnel syndrome includes numbness on the inside of the hand and in the ring and little fingers. The numbness is often felt when the elbows are bent for long periods, such as when talking on the phone or while sleeping. The hand and thumb may also become clumsy as the muscles become affected.
Keep in mind, however, that hand numbness can occur for a variety of reasons. It can even be from a nerve problem where the nerves originate in the neck. Your doctor's examination can help locate where your problem is coming from.