Was this area painted in an attempt to hide existing corrosion?
I think not. I doubt it's original Piper paint, as I doubt that Piper would paint the plumbing, but the paint was uniform in the area, and had been there a while.
Ebbie,
The corrosion in your photos has been there for many years. That type of corrosion does not "suddenly appear". As it is intergranular exfoliation corrosion, once it starts, it's really hard to stop. Corrosion preventing liquid is the best hope, but that spar is way past that!