This is a new collage of Dan Rather and the mystery man from the Dallas Police garage, and I am strongly convinced that it is the same man. There is the excellent match of the large ears, the bushy eyebrows, the nose, the baggy cheeks, and the hair. For another man to look this much like Rather would be startling anywhere, but for him to be in the very same place that Rather was focused, is mathematically, like winning the lottery.
So, I conclude that's Rather, but what I wonder is: why would he lie about it? He claimed to be at KRLD, the CBS affiliate in Dallas. You can hear him say it at the link below, at 2:08, that he was at KRLD "subanchoring." You'll hear him say that the famed CBS reporter Nelson Benton called him on the phone, saying "you better get (the coverage) here now because this thing is moving pretty quickly." What thing? Oswald was, supposedly, going to be walked 30 feet to a car and driven away. So, what expectation did Nelson Benton have? It sounds like he and everyone else knew that something momentous was going to happen. "Hell! This is happening!" What did he think was happening?
But, if Rather was in the garage, and either he was, or there was a startling lookalike of him there, why wouldn't he admit it?
I could only speculate about that.