It is possible to have a bad sensor in a camera, such that it produces an abnormal color cast. However, that is extremely rare and highly unlikey. I can only recall one story over many years where the user reported fixing a color problem by having the sensor replaced.
Cameras of the same make and model can produce slightly different colors under identical conditions. However, those differences are usually very slight and insignificant.
Cameras of different makes OR models usually produce different colors, and those differences can be significant. Different sensor technology can contribute to those differences, but again only slightly. The main differences comes in the camera profiles used to process the raw files.
In spite of Adobe's best effort, and regardless of their often repeated claims otherwise, the "canned" profiles they distribute for each camera make and model are not consistent. They are definitely not consistent across different makes (Canon vs Nikon), and they are not consistent across different models of the same make (Canon 5D vs. 7D, vs. 5D2).
And while the Adobe canned profiles are advertised as emulations of the in-camera jpeg shooting styles, they are usually quite different. The numerous forum posts asking how to process a raw file to look like the in-camera jpeg is the strong evidence of that.
Some recommendations for you:
First, using one of your raw shots, cycle through the various camera profiles in ACR. Do they all look "magenta" to you.
Second, shoot some RAW+jpeg, using the various in-camera jpeg styles. Do the jpegs look magenta to you? If they do, then you may have a serious sensor defect. If they don't, that proves the sensor is OK. The problem is in your raw conversion. Carefully review all the ACR settings, including camera profile, to make sure you aren't picking up some wierd default settings for the 5D2.
Third, search and download some 5D2 raw files from another source (dpreview has some in the camera reviews). Process them on your system. Do they have the magenta cast? If yes, that's more evidence of bad default settings for the 5D2 in your ACR config.