Here's the thing - most of us, when we think of a cam, we think of an eccentric (which is defined as deviating from a circular shape) - the cam lobe on a cam bolt has a circular lobe, the exact diameter of the bolt it replaces - what makes it a cam is that the remainder of the bolt has a smaller diameter with an offset axis - the "secret piece" and the key to how it works is the tabbed washer, which has an inner tab that occupies the space left by the reduced diameter, forcing the bolt to function as a cam as you rotate it.
So yes - it's a 12mm cam bolt but not just because it replaces a 12mm bolt, but also because the diameter of the cam lobe is 12mm - so if you ever have a cam bolt and need to know the size, just measure the cam lobe - or - if you need a cam bolt for a vehicle that is not listed, just measure the diameter of the existing bolt - which by the way is how I learned this - I needed bolts for a Mitsubishi Pajero iO - a little 4WD about the size of a Vitara.