Is there a way, from an API standpoint, to determine whether a user has the ability to update/edit a particular instance of an object?  As the documentation describes, you can enable security at the object level but also at the instance level using territory management and/or sharing rules.  We tried using the MayEdit field but discovered later that this is not a standard field found on all Salesforce orgs (some of our older customers do not have this field exposed at all).  I tried reverse engineering the process by querying the respective "Share" table, if it existed, and the Group, UserTerritory tables.  Unfortunately there are some pieces of information I could not retrieve that would aid in my search.  For instance, I couldn't find a way, via API, to determine what sharing model (Private, Public Read/Write, Public Read Only) a customer applied to an object.  Is this information queryable/retrievable  somewhere?  DescribeSObject only gives object level permissions.  Anyways, if anyone has some insight on this topic, I would like to hear from you.

- Ed