I have owned 3 of them in the past 7 or 8 years and know of 3 or 4 more here in Central PA. Every time I see one for sale I find it hard to believe they only made 390 of them because they seem to keep popping up for sale. Tough machine to sell even though it is "fairly rare" and I think the reason they only made 390 of them is it just isn't a very good or popular machine.
The crazy thing is typically they are in pretty nice shape because they must not have gotten much play in the arcades back to the day. Odd theme & backglass, so-so gameplay, and really not much going for it compared to other games from that era are all reasons low production makes sense and low demand also makes sense.
Steve Young still has NOS playfields for them cheap and I doubt he will run out of them any time soon.
In any event someone will want it because some people like rare & unusual stuff. Best of luck with your sale!