See this link for full details on camera support in Camera Raw versions:
Snip taken from link above:
You’ll also note that ACR7, available with Photoshop CS6 beta, is lagging the most in updated camera support. This is based on when we lock down or “bake” the code for each release. Even though ACR7 was only released last week it was “baked” before Lightroom 4.0 and Camera Raw 6.7. Similarly, Lightroom 4.0 was finalized before Camera Raw 6.7. We’ll get Lightroom and Camera Raw in sync soon but in the interim, here’s the latest incremental support list for each product, relative to Camera Raw 6.6 and Lightroom 3.6:
ACR7.1 will have the superset of all currently supported cameras in ACR6.7 and LR4.1 plus a few extras.