I didn´t find any block number 4369999 in the ETH private key. Who knows what it means?
You won't find that in any key. It's a block number. For non-technical person, just try to find out the time stamp which is a particular date and time when that block was mined.
And private keys, so far your wallet is not on an exchange you're in good position to receive the fork give aways. Same as in BTC.
Your private key are your private access to your wallet and all associated asset.