Adding the one check packaging can't give you: Genuine Check.

• Jade Plus or Jade Core: the Blockstream app prompts a Genuine Check during setup. Each unit has its own key whose public half Blockstream signed at the factory, so a clone can't pass the challenge. Already set up, or using another app? Run it over USB at verify.blockstream.com. If it fails, stop and contact Blockstream support.
• Jade Classic (the original model): no Genuine Check, so rely on where you bought it, an intact box, and the device booting straight into fresh setup with no existing wallet.

A year in a drawer also means old firmware. Update it through the Blockstream app (Plus can also do it air-gapped) before you create the wallet you'll keep.

Then: let it generate the seed, confirm a receive address on the Jade screen itself, send a small test amount, and check your backup before moving real money.

Blockstream's guide: https://help.blockstream.com/blockstream-jade/set-up-transact-recover-your-wallet/perform-a-genuine-check-with-jade