If by Red Cubs, you mean the 82 Series, i.e., 482, 582, 682, 782 and 982, the answer is both (well actually MTD came later, it was Cub Cadet Corporation aka CCC for a short while). It depends on the serial number. Here's a chart that has the serial number breaks.
The belly of the IH built 82 series were painted red and built in the Louisville plant. When MTD started building them in Brownsville they painted the belly black so there was commonality between the Red IH tractors and the Yellow CCC tractors.