Yes, that is the legitimate product key for AutoCAD Mechanical 2012 (32-bit and 64-bit). It is required during installation or activation to differentiate Mechanical from plain AutoCAD or other verticals (e.g., AutoCAD Architecture 2012 uses 185D1 ).

AMD Athlon/Opteron or Intel Xeon/Pentium 4 with EM64T & SSE2 support Disk Space 3.0 GB to 3.6 GB for installation Display 1280 x 1024 resolution with True Color Installation Steps Demo: Installing AutoCAD 2012 - Part 1