1) Who did the last camblet change? Any other symptoms?
2) Push your weight over the strut, does it move?
Cooksport springs are pretty highly rated FYI. I'm yet to see a poor review. The shocks are pretty firm as standard though.
3) Sounds a bit like a fluid issue. Pagids are quite expensive...
I got a brand new set in summer 2011, the speedline decal was the same and there was some marking either side of the valve, I don't think it has the others though, not on the outside at least!