I have a for-test-only wallet.dat created with v0.1.3 and the consistent "magic number" before my private keys is: 0x01130201010420 but that wallet only has two keys. (...)
That's a very helpful post, so please don't take my little nitpick the wrong way, but, the way you've written it looks to me like you might not realize that your test wallet actually
does match the 12-byte pattern from the post that you're responding to (if you look carefully at your screenshots, then you'll see that your 7-byte pattern turns into the longer 12-byte one as you keep scanning left).