And then a different hash from the hardcoded value in the code? Not quite sure. You need to verify your sources. You can easily verify the hash of the pre-genesis block yourself: https://www.reddit.com/r/btc/comments/7o0ejr/has_anyone_trie...
If you mean a different hash from the actual genesis block of Bitcoin, released on 3rd January 2009, of course it's different. We're talking about two different networks.