Probably different patch manufacturers with different licensing agreements with Texaco.
From Google search:
The TM symbol can generally be used by any person or business to indicate that a particular word, phrase or logo is intended to serve as an identifier for the source of that product or service. The R symbol indicates that this word, phrase or logo is a registered trademark for the product or service.
The round Texaco logo was used until 1965 when it was replaced with the 6 sided logo that was used until 1982.
Last edited by SandPCollector; Fri Mar 19 2021 09:26 PM. Reason: Added more