Are you sure its the same buck? The bottom pic bucks beams look like they hook up, and the top one looks like they go out and hook back in. Also, top pick buck looks like his right g2 is alot shorter than his left side, where as the bottom pic, the g2's look pretty even. Different angles though, and angles can change the way the rack looks.
But if it is the same buck, he is a hard one to age for me anyways. In the top pick I would call him a 2 1/2 year old, the bottom pick I would call him a 3 1/2 year old, that is going off his body alone.
But every buck is different, so I really don't have a clue on this one.