I took a brief scan for gas pumps of the other three owners. Standard of Indiana demonstrates the same behavior as Conoco. I didn’t find any photos of their stations with the M&S 70 (although I only gathered around 30) and I found their advertising to contain competitor products. Here is a 1939 Standard Indiana ad showing the Gilbarco 80 and another ad from 1940 showing the Tokheim 36B.

I found a mixed bag for Mobil. I found some station photos with the M&S 70, but also many others with different gas pumps. I also found several Mobil ads showing the M&S 70, but I also found two showing competitor pumps.

Sunoco demonstrates a consistent and strong pattern of using the M&S 70. The majority of the ~20 gas station photos I found showed the M&S 70, and the Sunoco advertising consistently showed the M&S 70 in their ads.

Standard Ad w Gilbarco 80 (1935) from 1939.jpg Standard Newspaper Ad from 1940 w Tokheim 36B #2.jpg