RETDPI - yep, birthday greetings are technically premature, since IX was created by reunumbering the wireless flight on 08/12/14.
As for the Dams battle honour - there was a campaign against dams in 1944, with the intent being to prevent the Germans from carrying out controlled flooding as US troops got in range. The Kembs dam was burst by 617, and IX hit the Sorpe with a few Tallboys (there was no time to train up either squadron with the UPKEEP weapon which would've been more appropriate), but being a tough old thing, the Sorpe didn't burst.
IX left a calling card in the form of a Tallboy which didn't go off. When the Germans were doing some maintenance on the Sorpe in 1958, they partially drained the dam and found a rather large, slightly malevolent looking 12,000lb item sticking out of the mud...