I too am skeptical that they know this is the same buck. Especially if it is truly a wild deer and even more so between the 1st and 2nd year. Spikes have no similarity to branched antlers whatsoever to indicate it is the same animal. I've only had one buck that I was sure of from his 2nd to 3rd year. So many have such typical antlers that it's hard to tell at all. For example I've had pictures of what I thought was a given buck only to get a picture later of two identical bucks at the same time. I would have thought it was only one animal if they had never walked in front of a camera together.
The part about a buck being a spike his 1st year not being a good indicator of his potential, I do believe. He might never equal a buck that is a 6 point yearling, but the spike can certainly grow some good antlers if he lives 3 years.