You are correct. The others who say ten terminals are not. I believe the plan was to have 7 semi circular terminals on the East side of the highway, but only 6 on the west side. I think the reason that there were only supposed to be 6 on the west side is because there would be no terminal across from AA's Terminal 3E (now C). That was where the Airport Marina Hotel (later bought by Hyatt) was built.
Note: One of the earlier plans for DFW was to have only one terminal that was 2 miles long.
[Thomas] Sullivan had come to believe that the elongated TAMS terminal reflected the past and present, but not the future. The news that came in September, then, after this summer of ruminations, should not have been a surprise. Sullivan recommended that the TAMS plan -- award winning or not -- specifying a slender, elongated two-mile terminal be replaced with a new plan worked out under [Gyo] Obata's direction in just eight short and frantic weeks. Instead of a single huge terminal, there would be four (with enough space for nine more) separate, de-centralized half-loop terminals. Multiple terminals would eliminate the congestion inherent in a single terminal, and the half-circles would provide enough perimeter for the airplanes to come right up to each gate. The terminals would permit separate and convenient parking areas for each terminal, speed up completion dates by permitting separate contractors for each terminal, and eliminate congestion of aircraft.
Each terminal would have three levels for separate functions -- the ground level for a service road, airline operations,and a transit system; the second level for passenger lounge areas and concessions; and the third top level for departures. All gates would be adequate to handle jumbo-jet aircraft like the Boeing 747. The 252 gates ultimately planned for DFW would equal the capacity of all three New York Airports combined.
Actually, that second paragraph is kind of confusing to me, seeing as how passenger lounges, concessions and departures are all on the same level today.