Yessir, SCJ oil cooler / horn setup are the same as the Mustang, as you said. The '70 Cougars used two different styles of interior, with multiple color options available for each: The "Standard" interior had a simple door panel stitching and small cougar emblem. Seats were high-back with vinyl seat surfaces. White standard interior pic below. Note that this car has the optional console, which has a wood-grain insert for all model Cougars for '70. This pic also shows a speaker grille in the door, which is correct for cars with AM/FM or AM/8-Track radio options. AM radio cars had no door speakers. The only noticable difference in the high-back bucket seats between '69 and '70 is that the '69 had the seat back release mounted about half-way up the side of the seat, while the '70 release was down at the bottom. Hurst T-handle shifter was the norm for 4-speed Cougars in '70. The guage pod in the console is not factory (I believe only the Shelby's came with those originally). The steering wheel in the standard interior was a 2-spoke center horn pad version, similar to that seen on the mustang, but with a cougar emblem in the center instead of a pony. The "Decor" interior had a more decorative door panel stitching with a wooden cougar plaque. Seats were high-back, with "comfortweave" material - except for the houndstooth, which were cloth. Pics below show a Black Decor Interior. Rear seats followed the same seating material as the front seats, and the panel stitching also mimic'd the front door panels. (this orange car was originally an AM radio car and had an AM/8-Track added later, which explains why no door speakers)
Decor interior cars received the 3-spoke "rim-blow" steering wheel, which had wood grain trim and a cougar emblem. Also notice the Eliminator dash in this pic. Eliminators featured black "camera case" finished instrument panels (XR-7 and Standard Cougars had wood grain panels). Also, Eliminators had a block off plate in the top center of the dash, which replaced the toggle switches seen in the XR-7.
A few other notes... Headliner colors were black for black interior cars (including houndstooth), and white for white interior cars. Dash pad was black for all Eliminators. I've included some pictures of the "black and white houndstooth checked cloth decor interior" as well (this is considered the "holy grail" combination with competition green). Door panels were the same as the black decor pics.