Inspection of the varobs and cx headers shows that the creation time header values are all IMDI (-32768) for cx files and 0 for varobs files. I don't think that inconsistency matters, it's a consequence of the way the fixed length header arrays are initialised.
Code that sets the fixed length header values for creation time has been removed.
Tested in sith with a bb build that uses this branch:
Inspection of the varobs and cx headers shows that the creation time header values are all IMDI (-32768) for cx files and 0 for varobs files. I don't think that inconsistency matters, it's a consequence of the way the fixed length header arrays are initialised.