Someone on the previous thread did some good research. I believe it's golden. Yes, RD does occasionally publish fiction but I believe, without heading to my city library's microfiche archives, that it is true.
Yes, the story was a winner of Reader's Digest's "First Person" story award - for unique, _true_ personal experiences. See page 214 of the Nov 1955 edition of Reader's Digest for more details.
I've always read it under the assumption it isn't true - but that it's such a wonderful story Im going ot pretend it is anyway :)