Is there a unique field in the Clarizen project that indicates it is linked to a corresponding Saleforce object?

Hello Karen,

Yes, the External ID custom field of the project in Clarizen will inherit the Salesforce ID - you can differentiate between project created in Clarizen and projects created from Salesforce based on the format of this field:

http://screencast.com/t/uXB9rmBJo8W

Rob