As Energi Gen 3 is based on a different kind of blockchain, all balances need to be migrated.
At a specific time (block), Gen 2 gets locked from any further transactions on the blockchain. At that moment, a snapshot is made with all the balances, which gets imported into Gen 3. Unfortunately, this is not just a simple "copy and set over" action, because we do not own and control the Gen 2 private keys, and we did not create (nor do we own) the Gen 3 key pairs.
Therefore, the final migration needs to be done by the users themselves by creating a Gen 3 address (holding their private key) and by initiating the migration with their Gen 2 private key.
The short answer is no. You do not need Gen 2 Energi Core Wallet to fully sync with the Gen 2 blockchain before migrating the funds to Gen 3. We recommend you verify your wallet balance on Gen2 Block Explorer before starting the migration.
Details on how to migrate using Energi Core Wallet can be found on the page below:
Gen 2 migration approach is targeted at average users with a standard keypool size. The theoretical maximum for this method is slightly below 8k keypool addresses. Please use advanced Core Node migration approach instead.