I'm sure some of it is fine. Maybe you could find what seems to be a reputable company who will tell you when it was manufactured. I would avoid somebody just trying to unload their old stock.

According to MAS epoxy:

"What is the shelf life of these products?
The resin has an infinite shelf life and the hardeners have a shelf life of a minimum of 1 year in a closed container."

Many of us have used epoxy that's a couple of years old without problem. But, I'd rather start with fresh stuff in case you have leftovers. The hardener eventually starts turning brown if I recall