I saw that one this morning. Despite the not-so-great picture, I can see that is a very early '77. It's very similar to #617, which I think is still in Europe. I wish they would post a better picture of the logo.
I am guessing, after reading the ad, this guy is a player, now inactive or maybe retired, he has had this bass for 40+ years and priced it based on what a new Series I prices out at. I see a couple issues but I don't feel like nitpicking a classic. He'll sell it for less once the offers roll in.