I wasn't sure on this because my immediate reaction is that BCAAs are insuligenic and the answer would be no.
On the other hand I looked into this and one study suggested that BCAA supplementation pre workout didn't significantly alter the insulin response in comparison to the control group.
[h=1]The anabolic hormone response to a lower-body resistance exercise bout in conjunction with oral BCAA supplementation
Bill Campbell, Paul La Bounty, Austin Oetken, Mike Greenwood, Richard Kreider and Darryn Willoughby[/h]
Here is a quote from Layne Norton on the issue
Of course, how this effects rauwolscine specifically is another question as we are not just looking at insulin release, we are looking at insulin release correlated with rauwolscine breakdown.
I am not sure on that. For me, rauwolscine decreases my appetite significantly whereas higenamine and 3,3-diiodothyronine don't. I would try it both ways and see how the appetite suppressing effects differ and derive my answer from that.