Amigo @jdman00 buenas. don’t mix C3D and Autocad Metodologies you will mix everything and your mind will explode to soon!! 
First a litle back Ground, the C3D Way is to create an Style so you will need to create a diferent Style for each Block you want, this way you only need asing Style to your COGO Point. bad news i don’t know a way to asign a block to an style so you will nedd to do manually, may be some one could help you with this.
The autocad Way is much more simple, you only need a list of block names, and a list of insertion point for each instance, what controls the instance is the insertion point, it is the same for Familys in revit i let you a similar post !!
Hope this helps you!!