I've only seen Zodiac for sale a couple times in the 9 years I've collected. It doesn't seem to come up very often. You are right it is unusual. My first game was 4 Aces which is similar in layout. I miss that game and because it was my first I didn't understand how different it was. Like yours it had magnets on the playfield! That was a pretty cool feature, especially for 1970. Not to mention turret shooter, spinner, lighted backglass animation and four flippers. Pretty cool game. Congrats, I think you'll have fun with it.
Alex