Greetings again:
Since Randy (aka advertologist) brought it up, I took it upon myself to go through and catalog all off the confirmed Conoco issued states' souvenir decals. A presumption could be made that, with four different variations of each logo (Travel Club & Touraide; pre- and post-'48), there should be about 200 different decals in total (four each for each state, plus Wash DC, minus the two pre-'48 variations for both Alaska and Hawaii).
While a long way from completing the cataloging process, one thing has already become clear: In at least four already documented instances, I've come across exemplars where (at least) two different graphics variations were produced with the same logo type. Here I've shown two different graphics from the state of Washington, both utilizing the green-bordered (pre-'48) 'Touriade' logo.