If you first clear the fields, then save the document as a dotx template so that your users can use the template to create their documents, there will be no risk of anyone saving over it.

I note, too, that you've used a date content control in addition to your formfields. Content controls and formfeilds were not designed to work together and trying to use them that way can cause problems. Use a text formfield configured for date entry instead.

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Cheers,
Paul Edstein
[Fmr MS MVP - Word]