Really nice score - and looks in much better condition than I'd expect. Love the comic book style artwork on many of these older machines.

You might look to get some better floor protectors - looks like it left a nasty scratch on the wood floor.

I'm sure its a backlit number 1 rather than a score reel. This was common on older machines where there was more anticipation of rolling over the highest denomination score reel, but to keep cost down by not adding another score reel - particularly when most machines only had the three bank reels. In this case I'm sure the multi-ball feature prompted this.

The one place may well be a dummy of there are no 1pt score targets. If there wasn't an expectation of the thousands going above 1 and no 1pt targets, then having only two active reels would save even more on production costs (the reel factor behind these decisions). Not sure I've seen a game with an active one's reels where there were no 1pt targets.