Shown here are three Texaco leaded glass inserts (2 globes and 1 window insert) from the Henderson/Benjamin globe CD. In all three cases the "T" is completely different than yours. Based on that, I would say yours is a fake/copy. Or was it just done in a different time period by a different manufacturer? I kinda doubt it though. From my novice experience, it seems Texaco is pretty controlled and consistent with their logo!
Just my 2 cents
Always interested in Sunoco items!
Really want a Sunoco National pump add glass!!