Understood. I would suggest you reach out to the maintainers of the health portal to understand why these DICOMs lack the Software Versions (0018,1020) tag. It is a Type 3 (optional) public tag, so it is not required by a valid DICOM. However, this is not only required to determine slice timing, but is crucial for auditing errors or changes in sequences. I would not consider these images to be of archival qaulity.