Yes as per sdk, here is a berif diff between two.
You can secure these new
entities in the same manner as other Microsoft Dynamics CRM
entities.
- The security privileges available for
organization-owned custom
entities are as follows: create, read, write, delete, append, and append to.
- The security privileges available for user-owned custom
entities are as follows: create, read, write, delete, append, append to, assign, and share.
Muhammad Ali Khan
http://malikhan.wordpress.com