Yeah, I agree with somewhere around $4k, either a little more or less depending on how badly it's roached out and condition once someone sees it in person.
It's gonna need a complete teardown, either a new playfield or a proper restoration, either of which isn't cheap -- and in the latter case time consuming.
Cabinet is gonna need to be complete stripped, repaired, painted, decal'd. It's nasty as is.
Likely need various new parts above and below.... that'll add up.
Gonna be a lot of work, which takes time.
I'd be into that, b/c I like a challenge and TZ is on my short list.