besty, since you are bringing me into it, and after noting that you seem to prevaricate as much as you suggest R does in not giving a straight answer to a straight question (although I note that you have now conceded that your quote only refers to 'present truths')...I answered your question several posts ago to suggest that if there was a basis for selecting the WTS in 1919 it had nothing to do with unique truths but with the willingness of a group to change their beliefs in accordance with increased understanding of scripture.
I know that this is not entirely in accord with the interpretation of Revelation etc where specific assemblies were foretold two thousand years ago but that is as absurd as it is embarrassing. Whenever WTS representatives have given evidence in court (I think of both the Moyle and the Walsh trials) it is their willingness to correct their beliefs rather than their emphasis on uniqueness which they have acknowledged.