Colorado Springs gender guidelines

Here is a fun piece of history.

On June 2, 1997, when the initial Colorado Springs Guidelines were agreed on, Guideline B 1 originally read,

"Brother" (adelphos) and "brothers" (adelphoi) should not be changed to "brother(s) and sister(s)."

In The TNIV and the GNB, 2004, p. 425 - 426, Poythress and Grudem write,

"Examination of further lexicological data (as indicated in chapter 12) showed that this guideline was too narrow."

So then the following refined guideline was approved on Sept. 9, 1997,

"Brother" adelphos should not be changed to "brother or sister"; however, the plural adelphoi can be translated "brothers and sisters" where the context makes clear that the author is referring to both men and women.

What was the 'further lexicological data'? In Poythress and Grudem's own words,

"in fact, the major Greek lexicons for over 100 years have said that adelphoi, which is the plural of the word adelphos, 'brother" sometimes means "brothers and sisters" (see BAGD, 1957 and 1979, Liddell-Scott-Jones, 1940 and even 1869).

This material was new evidence to those of us who wrote the May 27 guidlines - we weren't previously aware of this pattern of Greek usage outside the Bible. Once we saw these examples and others like them, we felt we had to make some change in the guidelines."

Do Grudem and Poythress actually say that these lexicons contained "new evidence?" Is it true that those who wrote the gender guidelines had never looked up these 'gender terms' in Liddell - Scott or BAGD?