S&W 66 - No Dash

[colstontc1]

Picked up a nice 66 - No Dash today, serial number dates it to 1972.
It has a Case Hardened Target Trigger, wanting to know if anyone has one or has seen one like this. Did any come from factory like this or is this after the fact.
Just needing some info.

 

[Doc44]

I assume the hammer is correct. I believe the original trigger was replaced with the one currently installed on the revolver.

Bill