The single trigger in a Parker repro is NOT vintage, if I am not mistaken it is a different design entirely. Mr. Vicknair goes into the major problem with this trigger (idiots working on them) in his blog.

https://vicknairgunsmithing.blogspot.com/2024/09/un-botching-another-parker-repro-single.html

I’ve worked on a few single triggers over the years, and, rather strangely, never felt compelled to take a grinder to the sear noses. Others, feel differently, it would seem.

Best,
Ted