I do not doubt in any way that Seraphim23 was the first using the phrase in the environment that he described.
I did find however the story of Sharon McDaniel Kennedy, apparently written in 1999 (and according to Google's cache indexed at Sep 15, 1999 to be exact), where she said:
I believe with all my heart that Jehovah is the Hearer of prayers, and that he answered mine with the truth about "the truth". It became very clear, as I would read scriptures, what the real and correct meaning was, rather than what the Society’s interpretation said was the meaning.
See: http://www.towerwatch.com/Testimonies/sharon_kennedy.htm
Like Apognophos stated earlier:
When you think about it, it's a fairly obvious play on words