Larger rust spots indicate this may have been used for target practice.
Texaco was likely the leading brand on Route 66. Competing chains (DX, Standard, Union 76 etc.) tended to be concentrated in regions. Texaco bragged that it was "in all 48 states and Canada too."
This sign is at the Stokely Event Center, several miles from Rt 66:
www.stokelyeventcenter.com.