Yes, and it’s usually 42 months from the date of manufacturing. This means you need to replace this kit every three years. This is a safety measure because many people forget to check the state of their distress lights regularly. However, flares can usually be operable for much longer periods, so keep your expired flares because you will never wish you “didn’t have more flares”. For safety and legal reasons though, maintain a set of “current” flares that are not expired on board.
Nothing prohibits you to have the expired flares on board as a backup to your new ones – they may even come in handy. LED distress lights don’t have an expiry date, but they do have batteries that should be changed from time to time.