Found a Gottliebs Captain Card and have some questions

So, as the title says I was cleaning the gfs mother's basement and found a pinball machine down there. It is a Gottliebs Captain Card machine. They have owned the machine for around 25 years and it has been sitting in the basement collecting dust for about 15. She says it worked when they last used it about 15 years ago but I have not been able to try and run it yet due to its size and location.

Now, my question to you is what do I have here? Is this machine really a rare one as some sites say with only 675 units being made? If that is true what should I do to try and get this as ready as I can to sell since the gf's mother just wants to get rid of it instead if store it? Thanks.