Having fan slots doesn't necessarily mean you have radiator slot. There's multiple cases that have room for 25mm fans on top but that doesn't include the 30mm for the radiator as well. There's multiple cases that will have clearance for a 120mm mm based radiator but not clearance for a 140mm based radiator, even though they'll mount 120mm or 140mm fans. The ram or heatsinks on the motherboard won't allow for such, space is too tight. There's even cases that you can mount a 360mm radiator but only use 2x 120mm fans on the middle and rear ports, because of lack of 55mm clearance at the front, but you can use 3x 120mm fans alone instead. There's even cases with 2x 120/140mm fan ports that are spaced wide enough that radiators do not mount at all.
There's a difference between fan ports and radiator supported fan ports. The spec-04 wasn't designed to be brilliant when it comes to Watercooling support, it was intended for aircooling.