"With Celerity, Certainty And Security"

I was reading a recent news report about the demise of some of the smaller post offices in Texas and they used the following illustration which was described as "an early Post Office logo":



I have never seen this logo before, and in looking up the slogan "With Celerity, Certainty and Security" it seems it dates back to the time of Star Routes by private delivery services in the 1800's, yet even references to it in the National Postal Museum's website does not turn up this logo.

Anyone have any additional information on this graphic? Was it really a US Post Office logo back in its day? Anyone know when it would date back to?

Just curiosity on my part.