When you consider the cost of the rear site, forged flash chromed hammer trigger, internals, cylinder
and yolk and of course the 3" barrel (which is likely worth $150-$200 alone) you didnt do so bad....
Especially if the barrel is clean and you have a nice Model 66 with 2.5" snub barrel you dont mind swapping...
If you then sell the 2.5" barrel you will be way ahead IMO.
Probably a police turn-in, confiscation or involved in a crime, in a jurisdiction that mandates destruction of such firearms. Those of you who have seen "de-milled" M13 Aircrewmans (1911s, M-14s, etc.) know what this means, sadly.