According to the serial number on the headstock, it's a 78 not a 77. Strung righty so it'll need a new nut cut for it-you can't just "turn the nut around" as the seller mentioned. No pics or mention of the electronics being original or if they've been changed (a pic of the pots with appropriate date/code stamped on the pot would tell you the year of the bass a bit better)
No pics of the truss rod to see if it's maxed out or not. Pretty much all of the pics show cosmetic stuff. I would like to see more pics of the electronics and the heel of the neck. From what I see in the listing, it's a cool looking bass but I don't buy basses as artwork so I'd want to know more about its playing condition.

The one pot has an 80's something date. The truss rod is flush with the heal and clean. That's a good sign. The paint masking in the neck pocket doesn't look like a factory job. Might be a refinish.

Thanks!! So if the serial number corresponds to a '78 but the pots are '80s, where they changed, or is this common?

It's very common. It's pretty much anywhere from a 78 to an 80. Fender did this almost on a daily basis in that time period. From what it looks like, everything seems to check out. It's definitely not a 77. I'd put it at around an 80. Esp with that finish. I've never seen that color on any 70's bass. See if he's willing to negotiate on price a bit. Good find man! Hope you get it.