I can't tell for sure from the pictures on the Dell site, but all the racks I've worked with can - in theory - be taken apart.
The doors and side panels come off easily, then the rack consists of a top piece, a bottom piece with wheels or feet attached, and four corner posts. Looking at our Compaq racks (which look similar to the pics of the Dell), there are big, countersunk-headed bolts holding the posts to the base and top. The reason I say "in theory" is that I think it would take an impact wrench to loosen the bolts on our racks, they're tight.