Mystery Cone

On one of our beached bird surveys at the Salmon River beach near Cascade Head, we found a tightly closed cone on the ocean beach that we did not immediately recognize. We took it home and put it on our kitchen window ledge where it sat for several months in the sun. It is now opening and dropping seeds everywhere (which I intend to plant). It is 4 to 5 inches long (curved so hard to measure) and does not seem to have sharp spines on the scales.

So what is it? Our guesses are Knobcone Pine (Pinus attenuata) or Monterey Pine (Pinus radiata) or a hybrid of those. Can anyone enlighten me?