No. It's not. You have to figure that those specifications that say a given size will fit are only taking into account the extra space at each end of the radiator, like you see in the image below, so when you double that extra space like where the fittings attach, you are going to exceed the actual amount of space that was intended to accommodate only a single radiators end space, not two radiators end space.
Once you double up the area that those fittings or the ends of AIO radiators take up, you are talking about a significant increase in the overall length. It is always possible, so if you can get the exact measurements and compare it, you might get lucky, but I am very, very doubtful...