Lew was kind enough to send a link to Phil Hawksley's website on BMW paint colors.
It looks to me like mine is Bronco Metallic Brown. The seat is a Denfield? and was recovered - I haven't seen any paint code under the seat or anywhere else. I've tried to find out if this was a standard color in 1973 but from what I can see, the paint is original.
There are some pretty noticeable scratches on the tank but the paint on the fenders are in very good condition. Not sure I'll paint just the tank because it will be hard to match the color on the fenders but am thinking about it or maybe getting some touch up paint for the deep scratches.
If you know the paint code, please let me know.