Bip39 First 4 Letters. Although it takes advantage of BIP32 technique you may still import BIP39 seeds into Electrum wallet. Also apart from BIp32 There may be BIP44 Model which some wallet use for your era of seeds. The whole process of putting together a copyright wallet is similar to https://socialaffluent.com/story4058334/bip39-mnemonic-code-about-bip39-mnemonic