I asked this same question like a year ago because I ran into a fisherman while walking my dog during what I assumed was closed season. Unfortunately, I can’t find the original thread to give credit/specifics from whoever answered. In short, I believe the answer is it’s open year round because stocking stops at the 191 bridge. North of there, you’re good.
The entirety of ForEvergreen is definitely clearly posted C&R. These are not PFBC signs, so I’m not sure whose jurisdiction this is under. I vaguely remember rumors that the stretch would get the official state special reg designation, but haven’t heard anything lately.
Also, do some poking around and you’ll find a few threads on issues with property owners (and some funky property lines) that might be worth noting, though the most significant of these, the Penn Hills resort of doom, has likely been resolved since the property has continued to change hands repeatedly.