Every Valmet 412 that came into my shop was single trigger, and i installed double triggers "if" the costomer wanted them. (and a lot did)
Personally, i don't like a single trigger, so my 412 has had double triggers almost from the day it came in.
As for trigger pull, i don't know the pull, but it's a "hunting" trigger, not a target gun trigger, so i'll rate it decent but not excelent.
Hope this helps,
Drilling Man