Howdy
This is an early 'original model' Vaquero. It was made in 1994. It has the Ruger 'color case' finish. Which as has already been stated was not real Case Hardening, it was a chemical wash.
The 'original model' Vaquero was nothing more than a New Model Blackhawk with the frame contoured to resemble a Colt Single Action Army. The front sight was replaced with a simple blade like the Colt and the adjustable rear sight was replaced with a fixed sight groove down the center of the top strap, also similar to a Colt. But other than that, the 'original model' Vaquero was nothing more than Blackhawk with a re-contoured top strap. And the grip frame was steel, unlike the aluminum grip frame of the Blackhawk. I can clearly remember when I first bought the Blackhawk in the first photo that it felt kind of heavy. Sure enough, when I got it home a magnet showed me the grip frame was steel, unlike the grip frame of my old New Model Blackhawk that I bought in 1975.
This is an early New Vaquero. It was made in 2006 when Ruger was still finishing them with the 'color case' finish. Ruger stopped putting this finish on the New Vaqueros shortly after this one was made because there were a lot of complaints about the finish causing rust. For what it's worth, I have two of these, in addition to my 'original model' Vaquero and I have never had a problem with the finish rusting on any of them.
"So why the change to the long spur with the New Vaquero, for the Cowboy Action Shooters?"
Because that is what shooters were asking for. Shooters were complaining about how big the 'original model' Vaquero was, significantly bigger than a Colt. So the New Vaquero was introduced in 2005 and the 'original model' Vaquero was discontinued at the same time. One of the features of the New Vaquero, along with being the same size as a Colt, was the longer hammer spur, very similar to a Colt. That's what shooters were asking for. In addition to the change in the hammer shape, the cylinder pin was shortened, so it could be removed from the gun without removing the ejector rod housing. You could not do that with a Blackhawk or an 'original model' Vaquero. This also meant that you could loose the cylinder pin in the grass if you weren't careful, just like you can with a Colt.
About that longer hammer spur: with a Blackhawk or an 'original model' Vaquero the hammer spur was short enough that the gun could be sighted with the hammer down. You can't do that with a Colt, the spur is too long and is in the way. You have to cock the hammer to see the sights. Same with the New Vaquero when it first came out, you had to cock the hammer to see the sights. Other hammers are available now, but what's the point? It's a single action revolver. You can't shoot the thing until you cock the hammer, so what does it matter that you could see the sights with hammer down?
Of course, people being people, as soon as the New Vaquero appeared, there was an immediate hue and cry for the old model, despite the fact that Ruger gave shooters exactly what they had been asking for. A single action revolver that more closely resembled a Colt.
Oh yeah, there was a lock hidden down inside the grip frame, but unlike S&W it was completely invisible unless you drilled an access hole for it in the grips. They even provided a dimple on the inside of the grips to show you where to drill. Or you could completely ignore the lock like most of us did.