It depends on what you used to sign the transaction in the past. Many years ago there have been some tools that had bugs that led to generation of weak signatures that could be used to reveal the private key. One example is the old blockchain.info wallet. In that case the safe approach would be to import your private key into one of the popular wallets (such as Electrum) and sign the transaction again.
But if you used a decent tool such as bitcoin core to sign the transaction, there is nothing to worry about.