So, your saying there's a chance? 
How will I like working on it? Anything I need to be watching out for specific to Stern of that era? I've never been in the backbox of a classic stern.
Be sure to remove the balls from the trough before transport. The switches can easily go out of adjustment with the balls bouncing around in the trough, and cause the game not to start up. Also, there's some parts on the speech board that are impossible to get, so I'd check to make sure it talks before you buy it, or you'd be SOL!
Other than the sound board, they are identical to classic Bally SS games.
Also, this game doesn't come with a knocker from the factory...all driver transistors are used for playfield functions, so no, yours isn't missing.