No they did not. There were not many sold by GE. They were high HP per axle. The U30B and B30-7 was the closest the Frisco purchased.
I've wondered that as well. Doing some reading tonight, I think I found some clues that might answer why the Frisco did not take an interest in something like a U36B. https://en.wikipedia.org/wiki/GE_U36B Looking at the wiki article, the Seaboard opted for a higher gear ratio to achieve a higher speed of 75 mph, which would make good use of the higher HP per axle. This would only make the units useful for high speed intermodel service. Looking at timetables from 1975, the major lines in the system had a speed limit of 55 mph, with exceptions of 60 mph for trains QLA, 32 and 33. To my knowledge, all the Frisco second generation units were capable of 65 mph, which would meet the needs of the system. So they didn't need the extra speed, and, just guessing here, did not want to spend large amounts of money on locomotives that could only serve one purpose. They could better spend similar money on locomotives that could serve just about any purpose.
Back in those days EMD had a great sales and support and supply system working for them too. Those GP38-2s and GP40-2s were hard to beat. And as Ethan said, they fit right into the operating plan.