At John's suggestion, I did some follow-up searching today. First off, there is no entry for the quote in the urban legend site Snopes, though I'd imagine it's only a matter of time before it is added. I did find a further history of the quote and the mini-controversy it stirred afterwards here. As did the previous post's link, it does make note that the exchange was between Bush and a "...fully accredited reporter...present by invitation as a member of the press corps". I also found this link, which reports that there was a comment by White House Counsel C. Boyden Gray months later that addressed the controversy, and this comment in turn was reported on in The Minnesota Daily newspaper.
Gray's statement was neither an affirmation nor a denial of what the President said, so this particular situation comes down to a case of a he-said/he-said. However, I'd like to end this post on an upbeat note by including a quote from the 43rd President that I found during my searching:
"Americans practice different faiths in churches, synagogues, mosques and temples. And many good people practice no faith at all."If Bush Sr. did indeed say what he is accused of saying, then this quote would signify a marked improvement in his son in at least one area. There. Never let it be said I never said anything nice about the guy.