Hi WH,
I purchased directly through Carenado. I think the 1121 file is the 2nd service pack.
Viewing the Carenado "My Products -> Update" link shows he updates below...
B200 KING AIR HD SERIES FSX/P3D
(Exp.) B200 FSX - Service Pack 20121105
(Exp.) B200 FSX - Service Pack 20121121
The .Zip files are named BE900X_SP1 and BE900X_SP2, while the main installer file is BE900X.