I understand that Cosden refined out of Tulsa and Frisco shipped them out. That would have been early 1900s but I'm sure the cars hung around even after Cosden was replaced. These are probably not anything like the proto (if you can even find a photo), but apparently they were a triple dome, at least. I did 4 of them.
I found Cosden & Co (COSX) in the 1919, 1925 and 1930 Official Railway Equipment Registers. The 930 and 940 series cars were built in 1925-1926. According to some online sources, Cosden & Co was taken over by Mid-Continent Petroleum in 1925. (See https://www.okhistory.org/publications/enc/entry.php?entry=CO065) By 1930, the Mid-Continent name was apparently being applied to the former Cosden cars, but they kept their COSX reporting marks and numbers. By 1935, they were showing up in the ORER under the Mid-Continent name, still with COSX reporting marks and numbers, which they apparently kept until at least 1953 (the last ORER reprint I have.) There have been a few AC&F builder's photos shared on Facebook groups such as Pre-Depression Era Railroad Modelers. These may have been taken from Al Westerfield's CDs of AC&F builder's photos or some similar source. The paint scheme and car numbers on your models seem to have been taken from the AC&F builders' photos, and while they might not satisfy rivet-counters, they look reasonably close to the three-dome tankers to me. I certainly wouldn't turn them down as interchange traffic.