Hi Rob & Cetera,
You're right about the chainring being mounted on the inside, but after enlarging the photo I'm pretty sure there isn't any shoulder on the inside of the crank arms. (For you Macsters who don't know this already, to enlarge a photo or page, go to "print" and then "preview" and then hit "+" until you get the size you want.) It won't print larger, but you can look at it.
Mark Fulton
Redwood City
California
USA