when i had to replace the radiator on my 6thgen, there was both denso and valeo brand available. rep at the autozone store told me that i have to go with the same brand that is currently installed in the car.
well, i think valeo was installed at that time (it was original honda radiator but manufactured by valeo), so i bought valeo only to find out that driver side fan's screw hole was not lining up. so i went back and exchanged for denso brand. this time, everything was lining up just fine, except one hole. they had no idea why holes were not lining up, and also did not have another one to check and see if i happen to bought a defect, so i said screw it and zip-tied the last corner.
well, my point is, he was probably referring to those 2 different brand.
edit: MT vs AT wise, if you are AT, then you should get one designed for AT for cooler inlet and outlet. however, if you have MT, the AT radiator comes with the plug that you can choose not to use those two outlets, so either one should work. well, just be sure to check if it comes with the plug. because the one i ended up replacing on 6thgen was AT radiaor, but i had MT. just FYI.