One thing I'd add is to learn the culture at your new company. They're probably proud of what makes them unique, and would like newcomers to embrace that.
Scott Weiss didn't just forget to put it in his blog post, he specifically didn't successfully implement a policy of adopting Cisco culture at the San Bruno office based on my later experiences there.
The IronPorters were still called that (now 7 years later). The office had different perks, different beer bashes, and rarely knew people outside their project thus ignoring most of the BU and it's culture.
I think you're completely correct, and it's a really hard thing to accomplish. He may have tried and failed, but I don't know as I wasn't there during acquisition.