Hi MG, at one year it should still work fine. Have you tried cementing a couple of pieces of scrap plastic with it - if that doesn't work, then the CA is past use.
I use a whole variety of CA glues, picked up at model shows, can't think what's on the workbench at the moment. (not at home just now), but for a simple plastic to metal joint, the cheap stuff from a Nickel and Dime store should be perfectly good enough.
S