Hmmm....Ruger must have played a little with them then. I went to their website and the first guns I pulled pictures up were of early 227- blue guns and they both had blue triggers.
It might be a case where the workman grabbed whatever trigger he had available, since blue and stainless guns pretty much come through there in random batches. At 1,000 pistols a day (I heard recently), it makes one wonder if the workmen give much thought to needing a blue trigger in a stainless gun and a stainless trigger in a blue gun. But if that is the way they are supposed to be, must be for aesthetics.
Chet15