Guys, I am actually in favor of using the terms "Old Vaquero" and "New Vaquero".
But PLEASE, FOR THE LOVE OF GOD, leave out the word "model" in either.
Ruger SAs made prior to the 1973 transfer bar guns are known as "old model". And the Ruger Old Army percussion guns internally use "old model" lockwork.
Every Ruger SA made from 1973 forward has the "new model" transfer bar action. Including the Old Vaquero, New Vaquero, etc.
"Old model Vaquero" described a gun that never existed: a factory fixed-sight pre-1973 Ruger SA.