I have a book, a gift from my wife, purchased from Amazon here in the UK and titled "Rickenbacker Electric 12 Strings", written by a Tony Bacon and published by "Backbeat Books"
http://www.halleonardbooks.com/product/ ... iteid=168&On pages 46-47 (full spread) there is a picture of a Rickenbacker 12 string similar to the one you describe. It gives no model number but is a 330 shape, six in a line tuners, "f" style sound hole, 2 x toaster pickups, "R" tailpiece, and described as "one of a number of prototypes made in 1964".
Weird thing is that even though the tuners are six in a line, they are still set at alternate 90% which seems to indicate the octaves as "banjo" style tuners.
Sadly, I never seem to have much luck trying to upload images but I hope this information might help.
Cheers........Brian.