Rossi Model 851 as a Diamondback clone?
I don't even like Diamondbacks but I think this comparison is insulting to the Diamondback. The Rossi features a S&W style rear sight, S&W cylinder release, S&W style grips, S&W side plate, and they are even marked in the same usual areas. Only a brand new revolver guy would see such a gun as a revolver clone. I can tell you know some of the differences, but I, like many others can see that the Rossi has a vent rib barrel, but NOTHING else in common with the Diamondback. Rossi and Taurus are S&W copies, not Colt. Whether the gun has the famed vent rib is inconsequential when discussing which manufacturer was actually imitated.
Here is the diamondback, a deluxe colt target revolver. Too many differences for the two to be in the same sentence.