When you try to rotate them, don't pry on the open end of the spring. If you make a tool (a small screwdriver sharpened to a chisel point works well) and drive it under the lower spring as close to the pin as possible. The pin is actually tapered and once moved usually comes out easily. This must have been a problem for Parker as it was changed in their re-design between 1910 and 1920.

I learn something every day, and a lot of times it's that what I learned the day before was wrong