My thoughts..
looking at this address, addr": "1N1SChDzQ1EyKm3nb5u6wGRyzhepYdNwEZ", It has not transacted. So, the program you are using is processing the wallet with your wallet passphrase, which is deriving a master key which in turn is decrypting all the Ckeys in the wallet producing the compressed addresses. (I don't believe compressed addresses were about in 2010?)

There are scripts about to convert compressed addresses to uncompressed so you could check all 200ish uncompressed addresses to see which ones have a balance. Again there are scripts to automate this.

You can then dump the wallet to get all the Ckeys. With the Ckey of the address with the balance and the passphrase master key,  it would be possible to decrypt that individual private key even if the wallet was corrupt.

I do have scripts that can do this which are not public but I am sure there are others out there..
Good luck