Compare apples to apples.
Compare say, a 1985 Model 19 to a 1985 Model 66.
The only difference in the trigger will be due to individual gun variations.

I've heard people say that blued guns have better single action pulls than stainless guns, but they get that deer in the head lights look when it's explained that the single action pull is confined to the interface of the hammer and trigger, and both guns used the same carbon steel parts.
One was color cased, the other was hard chromed...... Same trigger and hammer under the finish.

The only difference you'll feel between a blued S&W "K" frame and a stainless S&W "K" frame is individual manufacturing variations.