Yes, but...
http://www.rc-monster.com/forum/showthread.php?t=11650
FLM discontinued the adaptor and simply brought out a 3905 specific chassis- you may be able to get an adaptor from Mike though as a custom order.
Same reason why GorillaMaxx brought out the G4 chassis, so people could use the stronger 3905 tranny in the better GorillaMaxx chassis (trouble is I prefer the G2/3 design myself).