The Bell System Memorial site, along with http://www.telephonetribute.com/
has some great information. Highly recommended, but be warned you'll end up reading them for the rest of the day instead of getting any work done!
Just read there that Graybar was a spin off of WE electrical supply department.
I found a couple of files a while ago which are taken from a satellite radio technical talk show of a few years ago, and in one of the telephone-related discussions the subject of Graybar came up.
The old-time switchman said that at one time Graybar was the only source of Western Electric telephone equipment for the independent (non-Bell) companies.
There's actually a lot of interesting nostaligic telephone and radio/TV talk on those links. Go to http://www.centralofficeonline.com/
and you'll find two separate links about halfway down the page (the Tom & Daryll show).
Make sure you have plenty of time though -- Each clip is about an hour and a half!