of course the seeds are still good even after a year they will still pop if you store them properly they can last over 30 years. but I even read somthing about nl5 nevil lost the original mother but he had a bunch of seeds he got nl5 from origanally that where like 5 years old or so and just kept in a bag on a desk or whatever it was and him and shanti cracked them and got a good amount to germinate and they found a new nl5 mother. so the nl5 from mr. nice aint the original clone only but I'm sure they selected the closest to the original. but after 5 years not properly stored and they did ok you'll be fine.
There is only one way to know if your ceeds are viable or not, and that's to plant them. Remember, not even brand new ceeds from a vendor's shelf may give you 100% germination. Bad batches do happen.
But that said, there is absolutely NO REASON why properly stored ceeds only a few months from the vendor should NOT be viable.
I've recently had success growing out a 10+ year old bag ceed lifted from some low-end brown Mexican brickweed (see my sig below).