NOTICE - Trigger stop slot. I've seen that included with Combat Magnums into the mid-'80s. Was a trigger stop standard on the 14, 17, & 18 then?
When the opening for the trigger stop was eliminated I don't know
The opening for the trigger stop was eliminated from the frame around 1994 with the 66-4 (19-7) change, when they went to the drilled and tapped frame and new rear sight style.
…the gun has a target hammer and trigger, they never came that way did they?
but target hammer and / or target triggers were legit options.
Never say never!
Although the TT/TH were available options on many models into the ‘90s, it seems they were an option on only the earliest M66’s; before 1974.
It also wasn’t a cataloged option on a 2.5” M19 but like M66’s, I’m sure there are many out there that will letter as having shipped with them.
Then there’s also the “Critical Moment” 66-3’s from 1990 that had the TT/TH and trigger stop.
Yes, not original but at least you have the Border Patrol trigger, which is the best compromise trigger S&W made for the K-frame. Works well for both SA and DA fire, whereas a true "target" trigger is about worthless for DA fire.
I tried Googling the Border Patrol trigger thing, as M29since14 mentioned it, can't find any info though..
I hadn’t heard of it called that either but I like it!
One of the reasons it’s taken me so long to post this is because I was hoping to find a mention of triggers by Bill Jordan but I haven’t been able to.
Even though a TT was not a cataloged option on the 2.5” M19, two quickly come to mind that had the smooth, wide Border Patrol trigger. The matte blue Dept of State and Connecticut State Police 2.5” Model 19’s.
Neither were the grips shown on your gun. All 2 1/2's were shipped with magna's.
Yup, I agree with you. But, it does make me wonder why S&W took the time to stamp the serial number in the yoke cut of this M19 if it didn’t leave the factory with stocks that covered the one on the butt.
Never say never?
The target triggers and hammers weren't available even as options on the 66-1's.
I looked again at your pictures and noticed your 66-1 still retains the trigger stop. They were mostly eliminated with the 66-1's and I've seen very, very few that still have that feature.
The trigger stop was eliminated in 1978, unless it was equipped with the optional TT/TH, which wasn’t a cataloged item for the Model 66.
That trigger stop does look to be for a .265 service trigger though. The ‘exposed part’ of a stop for a target trigger was flatter.
Even if it was customized by a previous owner, that’s still a really sweet 2.5” M66 you got for a nice price ladder13. Enjoy it as is or configure it as you see fit.
, now you really have me thinking about a letter. 
