Model 27 nickel front sight question

[Eddietruett]

I know this sight on a nickel 27-2 6" barrel is not standard, but was this ever offered as an option from the factory. Not the best picture, but looks to me like it's been changed.

 

[VM]

Sorry, but NO
Looks like Modified patridge sight

 

[bigggbbruce]

Looks like it's been machined in. Ouch.

 

[ms]

Looks like there's a pin, so should be replaceable. Has the barrel been modified? Can't tell, strange reflections.