Your links don't take you to any current articles that I could see. I found one more current that expands upon the article you posted quite interestingly. They say the earlier version, (the one with the prettier girl as you stated) was probably the first one done by him, the second one is calculated to have been done a decade later as a age progression painting showing what he thought she'd look like later in life. Quite an interesting read if you want to read it and it goes a bit more into the battle over the rights to it.
https://edifytrends.com/the-secret-battle-over-mona-lisas-prettier-twin/