Here is a photo of a couple of New Vaqueros underneath a 7 1/2" 'original model' Vaquero.
The hammers on these New Vaqueros are the hammers that were first available on them. Just like a Colt, the hammer spur was taller than that on the 'original model' Vaquero. And just like a Colt, the taller hammer spur obscured the sights until the hammer was cocked. The lower hammer spur on the 'original model' Vaquero does not obscure the sights. Doesn't really matter, you can't shoot the gun until you cock the hammer anyway. There are a couple of options available now as far as hammers on the New Vaquero. The SASS New Vaqueros have a lower profile hammer, I'm pretty sure it is a Super Blackhawk hammer.
The extractor rod handle on a New Vaquero is a bit more like a real Colt crescent shaped extractor rod handle than the one that came on the 'original model' Vaquero.
One other detail that has not been mentioned. The cylinder pin on the New Vaquero is shorter than on the 'original model' Vaquero. The longer cylinder pin was Bill Ruger's idea way back with the original Blackhawk. With the longer cylinder pin, the pin cannot be removed from the gun without removing the extractor housing. Bill did that because with the shorter Colt pin it is possible to loose the pin, particularly if it jumps out of the gun from heavy recoil while shooting. With the New Vaquero pin, it is completely possible to loose the pin in the grass if it jumps out of the gun from recoil. Ignore the pin in the pictured 'original model' Vaquero, it is an after market replacement pin.
By the way, I have demonstrated the way I always differentiate between the earlier and later model Vaqueros. Removes all doubt of which one I am talking about.