Are ID of default fields (or SharePoint components) in 14 hive same for SharePoint installed on different machines ?
Yes the Guid of the default fields like
Created etc. stays the same across machines. You can reference them with the SPBuiltInFieldId class. E.g.:
SPBuiltInFieldId.Title will give you the Guid of the Title field.
This link shows SharePoint Default field GUID(ID), Internal Name and Display Name..
and this GUIDs are not changed in any system. They remains same.