My rampage also has: "PCB made in China" written on it.
There front of the box has a nice X48 logo on it and the back of the box does indeed say X38 .

I used serveral programs to check the system status and to run benchmarks.
Some programs also list the chipset as X38, but this could be caused by me running older versions of tools such as cpu-z, everest and 3d mark.

But these small mistakes don't really bother me, for me the board runs fine and the temps are also ok'. When running my E8500 @511 fsb multi 7.5 the board runs no hother than 40 degrees while stressing with orthos for a long period.
I have noticed that airflow does have a big impact on the temps of the board, when using a intel boxed cooler it ran much hotter then when I used my zalman FS-C77.