It checks-out since the old version had both client and server which can use a modified bitcoin node to connect to.
Right on, man! Yeah it was a crazy time in the bitcoin world for sure. Went from 'hey, let's do this crazy thing with computers for a couple years and get this thing that could be considered theoretical currency!' to 'hey, now this is REAL currency..? Now how do I store it?!'
I was working with the Bitcoin core and Armory mostly at that crucial time. Then Electrum really streamlined things. When I saw it could run offline and work off the same blockchain as Core, I did all kinds of silly things. Electrum even provided a QR code that I tried to save as an AUTO CAD file. It really was like the wild West of cryptocurrency.
In 2012 I confirmed the mnemonic phrase worked and could access them at least through Electrum as it would at the very least give me access to the keys.
Now, here's the uncertain parts.
Electrum in Dec2011~Jan 2012 didn't used BIP39 word list but an old_mnemonic (
until v2.0 - 4Q-2015), they still host it in their GitHub Repo,
here:
https://github.com/spesmilo/electrum/blob/master/electrum/old_mnemonic.pyAnd even though it's the newer versions (
up to the latest) that uses BIP39 word list by default,
It's not BIP39 standard compatible so bruteforce programs that specializes in BIP39 wont yield positive results.
You are absolutely correct. I remember it was the very week they made the addition of the 2048 wordlist. I had a phrase made from the old list. I made sure when the new list was generated, the words would mean something to me. Like my favorite color, animal, etc. Except later after the latest mnemonic was crafted, I had the option of upgrading to a HD wallet type. Since I never had the funds live, I figured it was as cold as cold storage should be. What I had was a way to get to the key.
Lastly, let's consider that it uses the old mnemonic, since you may have used the versions with "key derivation bug" in 2011 (namely <0.31 and 0.34),
a program that's compatible with electrum's old seed may still get false-negative results.
You might have to audit those versions instead and build a bruteforce tool based from its code.
You got a forensic minded approach. Nothing is impossible, just very VERY difficult.

There are plenty of people that helped me before and others that inquired as to my progress. -snip-
Unfortunately, it's because of the premise that it's actually a BIP39 mnemonic based from the phrase "
I (you) created a BIP39 mnemonic".
That's despite the fact that BIP39 was created in 2013.
But here, you mentioned that Electrum generated it.
Now one of the goals is to identify the right version of Electrum that I used during that time in Jan 2012 but in all the years I've been at this, I've not seen one clear answer. Thank you for giving me confirmation on some things and helping me theory craft some plausible suppositions of what might have been and might be.