I sold a nice Neptune (with a NOS playfield) two years ago for $3k. My friend bought an unrestored Hit the Deck for $1,800 in 2015. He’s a top Gottlieb restoration expert, so $3k-ish will be its ballpark value when he gets done with it.
If you want to get one of these twilight-era wedgeheads—and another collector is selling it—the price won’t be cheap.