You have nothing to lose by trying them, give them a good soak before sowing, if they come up all well and good , if not you haven,t lost anything. Derekm.

Ive grown 3yr old ones before. as Derekm says nothing to lose except a week of time, but if you need to buy new you will still get a good crop.

The quickest way to find out is to put a couple on wet kitchen paper. If they are viable you will be able to see new growth quite a while before you would if you were waiting for them to emerge from the compost.