OrmLiteWriteConnectionExtensions.Save should populate GUIDs
The Save method will populate the inserted PK value if the PK is an integer with [AutoIncrement].
It would be useful to also have this method use the database's internal GUID generator (which creates sequential GUIDs) and thus populate back into the object a GUID generated in the db.
By default, database's will create a clustered index on the PK field, if the GUIDs are not sequential and the column has a clustered index on it, then performance will suffer.
You can use [AutoId] to auto populate Guid’s. Uses native RDBMS if it supports it otherwise OrmLite populates it.