A very nice original one is gaining value as we speak, because most of them have been "restored" with new everything. It's much harder to find an original.
A restored early 70's Fastback Mustang or a restored 1970 Camaro and a 9.5 condition original of each vary DRAMATICALLY in price. Pinball is catching up.
Antiques are the same way. Restoration tends to harm value from any antiquity that is 90% original, in almost every case.
People won't care much until the originals are selling for 12-15K and then you look at your restored one worth 7K and think, man... I pissed away 8K on that restore. I could buy a new Stern with that money. LOL!
Without any pics at all, it's probably worth 4-7K+. But that will depend strongly on finding the right buyer for that machine.