Interesting Southwestern Bell Sign

[Sargeguy]

This was up on eBay but the auction seems to have disappeared.  Interesting design-it looks like it may have been mounted on a truck or wagon or something:

[Fabius]

I saw that one. Notice it says Southwestern Telephone & Telegraph, not Southwestern Bell.

[Sargeguy]

Notice it says "Associated Companies".  Wikipedia has a surprising amount of info on the subject:

Southwestern Bell Telephone traces its roots to The Missouri and Kansas Telephone Company which was founded in 1882.[1][2] It was consolidated under the management of a single management unit of the Bell System with Southwestern Telegraph and Telephone Company of Texas-Arkansas, Pioneer Telephone and Telegraph Company of Oklahoma, and The Bell Telephone Company of Missouri—also called The Missouri Bell Telephone Company—on March 1, 1912. These companies comprised the "Southwestern System" of the Bell System. The latter three companies were legally merged into Missouri and Kansas Telephone Company in 1917, which was renamed Southwestern Bell Telephone Company.[3]

So we can date it from 1912-1917, when Southwestern T&T and a few other companies were consolidated but had not become "Southwestern Bell Tel. Co. yet?   Or is it 1908-12?