Nope. Totally different. They may use a Danfoss compressor but it is a different spec and until recently was heaps more efficient than the equivalent size Waeco.
The design of the fridge is also completely different from Waeco, much more robust.
It is one of the myths of 4WDing that the ARB fridges and Waeco's are the same. A little bit like saying because Samsung make nearly all the worlds LCD/LED screens that a Hisense TV is the same as a Panasonic.