I'd like to point out the possibility that the thief used the car to steal these records from someone else... I can think of one person in LA who has such an eclectic and ratty ass record collection, who goes by "northern crates" on twitch and is a good old friend of mine; he's spent years scouring record stores for rare and unheard Motown.

Probably not his stuff but you might want to try to figure out who just lost an entire record collection... it's probably not the thief's own.