Are atheroscleratic blood clots considered to be embolic?

Could be: Atherosclerotic plaque are not caused by embolus themselves but they can cause emboli distal to them or downstream. This is most of the time noticed in carotid artery disease and some cases of unstable angina.

If they travel: An embolism can be arterial or venous blood clot, atheroma (plaque) , air, fluid or debris. An embolus refers to one of these items travelling from one portion of the vascular system to another. The direction it travels an where it ends up depends on where it started and the direction of the bloodflow it is in. This is similar to leaves in a river- the embolism will go with the direction of flow.