I had the same thought. Just haven't had time to research yet.
I already own a set of '79 RD400F Daytona rims I'd like to use. I've heard the '79 Daytona triple tree can be used as-is on the RD350B. I"m hoping that also means I can use the whole front end, axle and all without spacers. I prefer 35mm forks, partially for the stability and partially because I have a GT750 35mm front end on my CB350 and it'd be nice to only need one set of spare clips-ons.