On Tuesday, McGraw-Hill CEO Terry McGraw broke the Apple Code of Silence live on CNBC. He gushed that Apple had a tablet computer that runs the iPhone operating system, for which McGraw-Hill, one of the world’s largest publishers, would provide customized content. As a result, Steve Jobs removed McGraw-Hill’s name from his iPad launch presentation on Wednesday.

Now, a McGraw-Hill spokesman claims Terry didn’t say anything on CNBC that he hadn’t already said on the company’s earnings call earlier Tuesday. And he’s right! AllThingsD provided this transcript:

”In the near future, you will undoubtedly see a McGraw-Hill e-book for the college market running on an Apple tablet. All our titles on CourseSmart, the industry e-book consortium, are already available to students on an iPhone operating system. That’s because CourseSmart developed an iPhone application last summer with support from Apple. The goal was to have core educational content available on the iPhone operating system, which also makes it possible for e-books to run on new Apple devices using that system.”

“Consider then the Apple tablet computer, which will be introduced shortly. There is a lot of secrecy about the introduction, but many expect that the Apple device will use the iPhone operating system. If that’s the case, we are confident that our CourseSmart e-books should run well right out of the box on any Apple Tablet. Stay tuned.”

Terry McGraw isn’t an idiot. It’s hip to cast anyone who publishes in print as clueless, but McGraw-Hill’s BusinessWeek was one of the business world’s leading voices for decades. The company owns Standard & Poor’s stock rating services and J.D. Power consumer satisfaction surveys. The company is also a leading textbook publisher, with the smarts to jump on board the iPad.

So, how did the point not get across to McGraw that he should have kept quiet on Apple’s new gizmo?

There’s one plausible explanation being floated among businesspeople I talked to today: McGraw’s apparent gaffe has also given his company incredible visibility. Everyone seriously tracking the iPad now knows McGraw-Hill is providing content. Can Hachette make that claim?

McGraw Hill VP of corporate communications Steven Weiss emailed me the following statement after a phone conversation on Thursday:

“As a company deeply involved in the digitization of education and business information, we were as interested as anyone in the launch of the new device, although we were never part of the launch event and never in a position to confirm details about the device ahead of time. On Tuesday afternoon Mr. McGraw appeared on CNBC in a wide ranging interview to discuss our earnings announcement and growth projections for 2010. His speculative comments about Apple’s pending launch, which he shared earlier in the day in a call with investors, were simply intended to suggest that if the new device were to use iPhone applications, many of our education products would be compatible with the technology and could be made easily available on it.

“Unfortunately, it seems that many mistakenly interpreted his comments as being more specific to yesterday’s announcement.”

“It is also important to note that only the products of trade publishers were featured in the launch event. Our digital education programs are not in that category and were never part of those negotiations.”